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American Railway Engineering Association

May 1997

Volume 98, Bulletin 760

BOARD OF DIRECTION

1997-1998

President

Mr. p. R. Ogden, Norfolk Southern, Vice President-Engineering, 99 Spring Street, Room 801 , Atlanta, GA 30303

Vice Presidents

Mr. D. C. Kelly, Illinois Central Railroad, Vice President-Maintenance, 17641 S. Ashland, Homewood, IL 60430

Mr. Rick Richardson, Jr., Canadian National Railways, Chief Engineer, 935 de la Gauchetiere Street, West Montreal, PQ-H3B 2M9

Past Presidents

Mr. B. G. Willbrant, Amtrak, Assistant Chief Engineer, 21 Berkshire Drive, Wayne, PA 19087

Mr. J. R. Beran, Union Pacific Railroad, Chief Engineer-Maintenance of Way Structures, 1416 Dodge Street, Room 1000, Omaha, NE 68179

Treasurer

Mr. W. B. Dwinnell, III, SEPTA, Railroad Division, Chief Line Maintenance Officer, 1234 Market Street, Philadelphia, PA 19107

Directors

Mr. J. R. Clark, Jr., CSX, Assistant Chief Engineer, 500 Water Street, Jacksonville, PL 32202

Mr. E. p. Reilly, Union Pacific Railroad, Chief Engineer-MAV Central, 1 860 Lincoln Street, 14th Floor, Denver, CO 80295

Mr. L. Anderson, Illinois Central, Superintendent Engineering, P.O. Box 2600, Jackson, MS 39103

Inc. Lorenzo Reyes R., FNM, Director Ferrocarril Sureste, Estacion Terminal, Montesinos S/N Colonia Altos, Veracruz, Mexico 91700

Mr. W. C. Thompson, Union Pacific Railroad, Director Engineering Research, 1416 Dodge Street, MC 3300, Omaha, NE 68179

Ms. C. D. Wylder, MARTA, Executive VP Operations and Development, 2424 Piedmont Road, N.E., Atlanta, GA 30324-3330

Mr. R. L. Keller, Montana Rail Link, Chief Engineer, PO. Box 8779, 210 International Way, Missoula, MT 59807

Mr. John Cunningham, Amtrak, Assistant Chief Engineer-Track, 3rd Floor, South Tower 30th Street Station, Philadelphia, PA 19104

Mr. Michael Roney, CP Rail System, General Manager-Engineering Services and Systems, Suite 500, Gulf Canada Square, 401 -9th Avenue, S.E., Calgary, Alberta T2P 4Z4 Canada

Mr. Walter Heide, Conrail, Assistant Chief Engineer-MAV, 2001 Market Street, Room 10-B, Philadelphia, PA 19101-1410

Mr. Gary Woods, Norfolk Southern, AVP-Maintenance of Way Structures, 99 Spring Street, Box 142, Atlanta, GA 30303

Mr. Michael Armstrong, BNSF, AVP-Maintenance Planning, 2600 Lou Menk Drive, Ft. Worth, TX 76131-2830

Executive Director

David E. Staplin

50 F Street, N.W., Washington, DC 20001

(202) 639-2190

American Railway Engineering Association

BULLETIN No. 760

MAY 1997

Proceedings Volume 98 (1997)

D. E. Staplin, Editor

CONTENTS

Cover Story: Reconstruction of Saco River Rail/Highway Bridge

Crossing: A Partnering Project in Design, Construction

and Finance 1

Proposed 1997 AREA l\/lanual Revisions

(Chapters 5, 8, 16, 18 and the AAR Scale Handbook) 9

Presentations at the 1997 Annual AREA Technical Conference — March 1997

1. Norfolk Southern Trackside Lubrication Studies — 1997 Interim Report. . . 67

2. The Philosophy and Development of AREA Seismic Design Criteria .... 77

3. Fracture Toughness Testing of AREA Grade B Hand Tool Steel 83

4. The Potential of the CFS MOW Estimating Relationships as a Basis

for Cost Allocation 91

5. Longitudinal Forces in an Open-Deck Steel Deck Plate-Girder Bridge . . 101

6. Improving Infrastructure Reliability Through Engineering Facility Management System Standardization 1 07

7. Managing Rail Resources 139

8. On the Benefits of Rail Maintenance Grinding 149

9. Service Level Live Load Stress Ranges on Hangers and Floor Beams

of Steel Railway Bridges 169

Technical Papers:

1. Development of a Recycled Plastic/Composite Crosstie 181

Memoirs:

Eldon E. Farris 189

Edward Q. Johnson 190

Index of Advertisers 201

Index of Consulting Engineers 201

Front Cover: Reconstructing the Saco River Rail/Highway Bridge in Saco, Maine.

Published by the American Railway Engineering Association, March, May, October and December at

50 F St.. N.W.. Washington, D.C. 20001

Second class postage at Washington. D.C. and at additional mailing offices

Subscription $81.00 per annum

Copyright© 1997

AMERICAN RAILWAY ENGINEERING ASSOCIATION (ISSN 0003-0694)

All rights reserved

POSTMASTER: Send address changes to American Railway Engineering Association Bulletin.

50 F Street. N.W.. Washington, D.C. 20001

No part of this publication may be reproduced, stored in an information or data retrieval system, or transmitted, in any form, or by

any means — electronic, mechanical, photocopying, recording, or otherwise — without the prior written permission of the publisher.

Published by the

American Railway Engineering Association

50 F St., N.W.

Washington, D.C. 20001

SUPPLIERS OF

equipment and Quality Repair Ports

RECONSTRUCTION OF SACO RIVER

RAIL/HIGHWAY BRIDGE CROSSING:

A PARTNERING PROJECT IN DESIGN,

CONSTRUCTION AND FINANCE

By: Vinay Mudholkar* (This is a synopsis of the presentation made to the AREA Technical Conference on March 18, 1997)

Guilford Rail System's east-west main-line traverses thru the heart of the City of Saco, Maine and is carried over Saco River falls on the bridge called Cataract Bridge. The bridge structure also carries busy Main street (Rt. 9) at grade across the railroad. The railroad bridge and highway bridge were interconnected structurally and were supported on common piers. This unique complexity posed a difficult challenge to the engineers of the railroad, DOT and City and required a strong part- nership between designers, constructors, and suppliers for the success of the project.

The highway/railroad bridge crossing is composed of 5 interconnecting super structures, which were replaced during the construction. The 4 bridge spans carry 2 main-line tracks, but at present time only one track is in operation. Due to the existing conditions, track speed was restricted to 10 MPH. Upon completion of the project, the speed was raised to 30 MPH. Cross vehicular highway traffic today is 22,250 (AADT) travelling at 25 MPH limit. Highway traffic growth was projected at 31,150 (AADT) by the year 2012. During the summertime tourist traffic is significant in the area and is a major revenue source to local merchants.The rail corridor has also been a subject of study for passenger trains and intermodal traffic and, therefore, the provision of double track was an essential capacity element.

A joint partnering effort was undertaken right from the start of the design process. This part- nering effort addressed concerns of highway traffic, railroad operations, requirements of utility com- panies, needs of local merchants and citizens affected by the project. Without such cooperation dur- ing the design and construction this project could not have been accomplished within the limited resources and time frame. The Project also was safely completed using safe construction practices and good project management.

The bridge has an interesting long history and has played an important role in local as well as interstate transportation. Major historic events were as follows:

1837: Town of Saco built 2 span roadway bridge carrying Main street over Saco River

1872: Boston and Maine Railroad builds railroad bridge thru, replacing roadway spans; the structure is now modified to carry two modes of transportation.

1884: Boston and Maine rebuilt the structure for higher capacity.

1887: Biddeford and Saco Street railway was built along the center of Main street crossing; intersecting the freight lines. Structure is now carrying three modes of transportation.

1919: All bridge spans were replaced; disputes arose amongst the owners; Public Utilities Com- mission of State of Maine stepped in and established a cost allocation for the construction and future maintenance.

*Deputy Director; MBTA — Former Chief Engineer; GTI — Boston, MA.

Bulletin 760 — American Railway Engineering Association

1939; Biddeford and Saco Sheet Railway discontinued service and removed the street railway tracks. Main street became part of Maine State Highway system and is now designated as Route 9.

1995: Design, specifications, plans were prepared and cost allocation was agreed upon for con- struction and future maintenance.

1996: Thru the partnering efforts, the highway and railroad superstructure was replaced within 24 days and a budget of 2.5 million dollars. Work was performed 24 hours per day, 7 days per week.

Public meetings and hearings were held in the City of Saco for public information and com- ments. City staff was extremely helpful in accommodating the project needs and clo.sely worked with the engineers in the entire design and construction process. It was realized that the project construc- tion could be speeded up by working round the clock, 7 days a week for 4 to 5 weeks. The very crit- ical element was the closure of the highway for that construction time period. Detour arrangements were worked out on the local roads and toll free access was provided to motorists to travel between two local exits of the Maine Turnpike. A bus shuttle was also arranged to transport local citizens who used to walk across the bridge using the sidewalks.

Amongst the suppliers. Premier Company of Portland. Oregon played a significant role in spe- cially manufacturing the railroad bridge crossing concrete deck, which supports the railroad's two main-line tracks, on the steel deck plate girders. For over 28 years Premier modular concrete railroad crossings have been successfully used in the rail industry and it provided expertise in modifying basic modules with appropriate structural requirements. The conventional wood crossing deck supported on wood ties was a constant troublesome area for repairs and was a rough riding surface. Roadway salt had leaked thru the timber deck causing major corrosion of the bridge steel. The ride over the timber deck at the crossing was certainly not comfortable to motorists, and timber fasteners used to cause problems. Frequent crossing deck repairs required street closure periodically, causing incon- venience to motorists and local businesses. The selection of Premier concrete crossing provided a smooth and durable ride quality surface eliminating repairs.

Speed and ease of total construction of the project was achieved thru prefabrication and simul- taneous work activities by a good work plan (Figures 1 & 2). Premier bridge deck crossing modules were specially designed and cast for this project. Premier modules were pre-cast reinforced concrete modules which used 7,500 psi concrete at 28 day strength. The average strength tested was 8,000 psi for concrete. Reinforcement used was 70,000 psi. Rails are encased in a continuous 85 durometer non-conductive TPE rubber boot, to dampen vibration and prevent abrasion of concrete against rail- steel. This also results in electrical isolation and less rail wheel noise. Rails can easily be replaced by removing center panels. Rails are locked into exactly formed recesses supported on a solid reinforced concrete base slab unit, installed on the bridge girders. The heaviest pre-cast concrete section weighed under 29,000 lbs. The standard module was 8.00 ft. long and 13 ft. wide and designed to carry highway loading of HS25 and railroad loading of E80. Units were 1 8 inches thick and rein- forced to carry the loadings. In all, there were 6 different module shapes used to accommodate the required bridge layout. Steel channels were used as shear connectors to provide connections to bridge plate girders. The units were cast at Premier's pre-cast facility in Ottsville, Pennsylvania. The units were quick to install and connect over the deck, and within 2 hours 90 feet of bridge deck was assem- bled for the support of the main-line rails. A standard boom truck was used to pull the rails and the center section was bolted down to secure the rail in the position (Figure 3). A % inch Fabrica pad was placed between the Premier modules and steel girders as the bearing pad to soften the deck impact on steel. Upon final placement, the modules were grouted at the connectors (Figure 4). The entire process was efficient and the main-line traffic was quickly restored over the bridge crossing without major delay to rail traffic (Figure 5).

Paper by V. Mudholkar

Figure 1

P

T ^

Figure 2

Bulletin 760 — American Railway Engineering Association

Figure 3

Figure 4

Paper by V. Mudholkar

Figure 5

Railroad girders were fabricated by National Eastern of Plainville. Ct.; using ASTM A588 structural steel, with yield strength of 50,000 psi. Highway pre-cast prestressed concrete girders were fabricated by StresCon of New Brunswick, Canada using 6,000 psi concrete. Prestressing strands were 1/2 uncoated 7 wire low relaxation ASTM A416 Grade 270 steel, with yield strength of 270,000 psi. The highway deck slab was cast in place using 3,000 psi concrete and 60,000 psi reinforcing steel. The new highway superstructure was supported on common piers of the railroad structure; but is not interconnected: thus separating ownership and maintenance responsibility.

Two railroad spans which were not under the crossing were strengthened by repairs performed by railroad crews and additional cover plates were placed, using high strength bolts. Structural replacement work was performed by CPM Contractors of Portland, Maine; with good quality and efficiency. Track work and signal work was performed by railroad forces very effectively. Roadway approaches were built by the City. Utilities were also relocated during the construction; from old structures to new structures.

These were: NYNEX Telephone conduit, water-line of Saco Water Company, sanitary sewer of City of Saco. fiber optics cables of U.S. Sprint and AT &T , Railroad signal conduit, overhead cables of Continental Cablevision, Central Maine Power and Saco fire department. All of the interested par- ties worked together in partnership and at reasonable costs. Excellent cooperation resulted in a good safety record, and no undue inconvenience was caused. Local merchants whose business were affected due to the Main Street closure were particularly to be thanked for their accommodation. Without their cooperation, this project could not have been accomplished within such a short con- struction period.

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Proposed 1997 AREA Manual and Portfolio Revisions

The following proposed Revisions of the AREA Manual for Railway Engineering and Portfolio ofTrackwork Plans have been recommended to the Association by the Technical Committee respon- sible for each after a letter ballot is approved by: (1) a two-thirds majority of the eligible members \ oting. and (2) by at least fifty percent of the total eligible voting members on the committee. They are being published here for comment by the general AREA membership and any other interested parties. Comments should be sent to AREA headquarters by June 15, 1997. These comments will be considered by the AREA Board of Direction in deciding whether to give final approval for inclusion of the proposed changes in the Manual and Portfolio Revisions, which if approved, go into effect August 1, 1997.

Proposed 1997 Manual Revisions to Chapter 5 — Track

Part 6 — Specifications and Plans for Track Tools

Page 5-6-4. Substitute the following revised te.xt for Part 6, Specifications and Plans for Track Tools.

Section 6.1 Specifications for Track Tools (1997) GENERAL

1.0 Workmanship

1 . 1 The steel used in the manufacture of all tools shall be free from pipe, porous centers, gross non-metallic inclusions or any other defects.

1.2 The chemical composition of percussion tools will be as stated in 8.3.1.

1.3 Unless specifically stated otherwise in the section on non-percussion tools, the chemical composition of non-percussion tools made from carbon steel will be as follows:

	Carbon	Manganese	Phosphorous	Sulfur
Grade	Min Max	Min Max	Min Max	Min Max
Carbon	.55 .70	.60 .90	.05	.05

1.4 All tools shall be made in a workmanlike manner and shall be free from cracks, seams, laps and other injurious discontinuities. Tools shall be free from burrs and sharp edges not specifically shown on the plans.

1.5 Eyes of tools with handle holes must be on center and in true alignment.

2.0 Finish

2.1 Percussion Tools

The body of the tool will be unpainted. The entire tool will be coated with a transparent lacquer type rust preventative.

2.2 Non-Percussion tools

The body of the tool will be coated with paint, oil or varnish to prevent corrosion. Each pol- ished cutting edge will be oiled or coated with a transparent lacquer type rust preventative.

10 Bulletin 760 — American Railway Engineering Association

3.0 Marking

3. 1 Each tool shall be legibly marked by stamping the following.

3.1.1 The manufacturer's name and/or trademark.

3. 1 .2 A code indicating the production lot.

3. 1 .3 For tools manufactured for use in the United States, any information required by the U.S. Department of Labor, Occupational Safety And Health Administration (OSHA). For tools manufac- tured for use in other countries, the requirements of that country will apply. This pertains primarily to lifting devices used by cranes but may also be required for other tools. The manufacturer will also furnish certified testing and/or other information with each item shipped as needed to comply with OSHA Standards or the requirements of other countries.

3.1.4 If requested by the purchaser, a specific marking indicating the railroad for which the tool was made.

3.2 The marking shall be located in a position which will not interfere with the quality or per- formance of the tool, and will not be removed by subsequent redressing.

4.0 Inspection

4. 1 The inspector representing the purchaser shall have free entry, at all times while the work on the contract of the purchases is being performed, to all parts of the manufacturer's works which concern the manufacture of the materials ordered. The manufacturer shall afford the inspector free of charge, all reasonable facilities and necessary assistance to satisfy the inspector that the material is being furnished in accordance with these specifications. Tests and inspections shall be made prior to shipment at the place of manufacture unless otherwise specified.

4.2 The purchaser may make tests to govern the acceptance or rejection in the purchaser's lab- oratory or elsewhere. Such tests shall be made at the expense of the purchaser.

4.3 Rejection — Material represented by samples which fail to conform to the requirements of these specifications will be rejected.

4.4 Material which, subsequent to test and inspection at the manufacturer's plant or elsewhere, and the acceptance shows injurious defects will be rejected and the manufacturer shall be notified.

5.0 Shipment or Delivery

Tools shall be properly packed for shipment to avoid damage. All bundles and boxes shall be plainly marked with the name of the purchaser, purchaser's order number, the name of the supplier, and the point of shipment.

6.0 Warranty

The manufacturer shall warrant that all tools are free from defects in material, workmanship and heat treatment, that the tools meet all requirements of this specification, and that any defective tools will be replaced free of cost to the purchaser. Certified test report may be requested by the purchaser.

PERCUSSION TOOLS

7.0 Scope

7.1 This section of specifications covers the contouring and metallurgical requirements for the manufacturing, ordering, inspection and acceptance of the following percussion tools.

7.1.1 Metal to Metal Contact Striking Tools

Spike Maul Plan No. 3-83

Double-Face Sledge Hammers Plan No. 13-83

Proposed Manual Changes

7.1.2 Metal To Metal Contact Struck Tools

Track Chisels	Plan No.	17-83
Round Track Punch	Plan No.	19-83
Track Spike Lifter	Plan No.	32-83
Nut Cutter	Plan No.	35-83
3 lb. Hot Cutter	Plan No.	36-83
5 lb. Hot Cutter	Plan No.	37-83
Drift Pin-Short	Plan No.	38-83
Drift Pin-Long	Plan No.	39-83
Spiking Too!	Plan No.	41-94

8.0 Manufacture

8. 1 Process — The shock resisting steel shall be made from carbon deoxidized special quality fine grain size alloy bar produced in accordance with ASTM A576, Standard Specification For Steel Bars, Carbon, Hot- Wrought, Special Quality.

8.2 Heat Treatment

8.2.1 Each tool classified in 7.1.1 and 7.1.2 shall be hardened by liquid quenching and subse- quent tempering in such a manner that the hardness range will be maintained to a sufficient depth to absorb the normal working stresses. This heat treatment shall be such that a fracture test of the tool will exhibit a silky, fine grained appearance according to Shephard Standard No. 6 or finer.

8.2.2 All tools made with alloy steel to be redressed without subsequent heat treatment shall be initially heat treated so that the hardness specified in 8.3.2 is maintained to depth from the end not less than the average cross sectional thickness.

8.3 Chemical and Hardness Requirements

8.3. 1 Ail striking and struck tools (7.1.1 and 7. 1 .2) shall be made of shock resisting alloy steel chemical composition with standard AISl residuals.

	Carbon	Manganese	Phos.	Sul- fur	Silicon	Vanadium	Molyb- denum
Grade	Min Max	Min Max	Max	Max	Min Max	Min Max	Min Max
Alloy	.51 .60	.75 1.00	.025	.025	1.80 2.20	.45	.35 .50

8.3.2 Hardness — All hardness tests shall be performed according to the latest revision of ASTM Spec. E-18. Frequency of testing should be performed to the requirements in the latest revi- sion of MIL-STD-105D, Military Standard Sampling Procedure Tables for Inspection Attributes."

8.3.2.1 All struck surfaces shall be 44/48 Rockwell "C" Hardness.

8.3.2.2 All striking surfaces shall be 51/55 Rockwell "C" Hardness.

8.3.2.3 All cutting surfaces shall be 56/60 Rockwell "C" Hardness.

8.3.2.4 All punch ends shall be 52/56 Rockwell "C" Hardness.

8.4 Hardenability

8.4.1 Alloy Steel — Composition of the steel shall be such that in the standard Jominy test the hardness is greater than 50 Rockwell C at 8/16 inch from the quenched end of the specimen.

8.4.2 Frequency of Testing — The steel manufacturer shall have conducted a Jominy test from the first, middle and last ingot of each heat of steel purchased.

Bulletin 760 — American Railway Engineering Association

8.5 Microscopic Inclusion Evaluation

8.5.1 Alloy steel shall meet the following requirements for inclusions.

8.5.2 Test Specimens — Specimens shall be taken from approximately 4 inch (100 mm) forged, square section taken from the top and bottom of the first, middle and last ingot. The specimen shall be Vs by -A inch (9.5 by 19 mm) and shall be taken from an area midway between the center and out- side of the test section. Procedures outlined in the latest revision of ASTM Method E 45 shall be fol- lowed.

8.5.3 Examination and Limits — Specimens shall be examined in accordance with the latest revision of ASTM Method E 45, Method D, using the modified JK Chart Fig. 12 of Plate III. The worst field in any specimen shall not exceed the following limits:

	A	B	C	D
Thin	3.0	3.0	2.5	2.0
Thick	2.0	2.5	1.5	1.5

8.6 Nondestructive Test Requirements

8.6. 1 To insure that all tools are free from defects listed in 1 .0, each tool shall be inspected after finished grinding by the supplier according to one of the following procedures:

8.6.1.1 Magnetic Particle Inspection in accordance with the latest revision of ASTM Method A-275.

8.6.1.2 Liquid Penetrant Inspection in accordance with the latest revision of ASTM Recommended Practice E-165.

9.0 Design

9.1 All tools shall conform substantially when applicable to the dimensions set forth. Dimensions for head contours as shown in Plans A-83, B-83 or C-83, D-83.

9.1.1 Head Contour

9.1.1.1 Heads of tools with a round cross section shall be ground to the comer contours pre- scribed in Plans A-83, B-83 or C-83.

9.1.1.2 Heads of tools with a hexagonal or octagonal cross section should also be ground to the comer contours prescribed in Plans A-83, B-83 or C-83. In addition, the arcs not tangent to the hexag- onal or octagonal comers shall be "blended" into a smooth contour similar to that shown in Plan D-83.

9.1.1.3 Punch ends shall have comer radii according to 9. I.I.I, but with no crown radius.

9.1.1.4 All ground surfaces shall be free of decarburization.

Non-Percussion Tools (Materials, Inspection And Physical Tests)

10.0 Clay Pick— Plan No. 1

Chemical composition for carbon steel as specified in 1.3, or alloy steel as specified in AISI 4140. No special tests required.

11.0 Tamping Pick— Plan No. 2

Chemical composition for carbon steel as specified in 1.3, or alloy steel as specified in AISI 4140. No special tests required.

12.0 Spike Maul— Plan No. 3

See percussion tools.

Proposed Manual Changes 13

13.0 Track Wrenches— Plan No. 4

Chemical composition for carbon steel as specified in 1.3. One wrench to be tested from each lot of 10 dozen or less by applying for 1 minute a load of 400 lb. at a point distant from the jaw end equal to 95 percent of the total length of the wrench without any spreading of the jaw or any perma- nent set in the handle. If requested by the purchaser. Section 8.6. Nondestructive Test Requirements will be adhered to.

14.0 Lining Bars— Plan No. 5

Chemical composition for carbon steel as specified in 1 .3. One bar to be tested from each lot of 10 dozen or less by applying a load of 350 lb. 9 in. from the end of the handle, with the point suit- ably secured 6 in. from the end, without leaving a permanent set in excess of 'A in.

15.0 Rail Tongs— Plan No. 6

Chemical composition for carbon steel as specified in 1.3. No special tests required.

16.0 Tie Tongs — Plan No. 7

Chemical composition for carbon steel as specified in 1.3. No special tests required.

17.0 Timber Tongs— Plan No. 8

Chemical composition for carbon steel as specified in 1 .3. Three pair of tongs to be tested from each lot of 10 dozen or less by suspending a load of 300 lb. or 400 lb. Work wi.se in the tongs with the handles in a horizontal position and supported 2 in. from the end. Deflection with 300 lb. weight shall not exceed 1 in. with no permanent set, and with 400 lb. weight deflection shall not exceed l-'/j in. with a permanent set not to exceed 'A in.

18.0 Spike Puller— Plan No. 9

Chemical composition for carbon steel as specified in 1 .3. One puller from each lot of 10 dozen or less to be tested in actual use by pulling a spike with a standard claw bar.

19.0 Rail Fork— Plan No. 10

Chemical composition for carbon steel as specified in 1.3. No special tests required.

20.0 Claw Bar— Plan No. 11

Chemical composition for carbon steel as specified in 1.3. In the manufacture of claw bars, Section 8.6, Nondestructive Test Requirements will be adhered to. One bar from each lot of 10 dozen or less to be tested by placing the claws of the bar Vi in. under the head of a standard spike, rigidly placed and so located as to hold the bar in a horizontal position while a shock load equivalent to that of a 200 lb. weight falling a distance of 1 ft. is applied to the handle at a point 5 in. from its end, with- out the toes showing any cracks or the handle taking any permanent set.

21.0 Track Adz— Plan No. 12

Chemical composition for carbon steel as specified in 1.3. Test one adz in each lot of 10 dozen or less by subjecting cutting edge to 5 normal blows on metal of the same composition as a railroad spike without breakage or serious nicking.

22.0 Carpenter's Adz— Plan No. 12A

Chemical composition for carbon steel as specified in 1.3. No special tests required.

23.0 Double Face Sledge— Plan No. 13

See percussion tools.

14 Bulletin 760 — American Railway Engineering Association

24.0 Tamping Bar — Plan Numbers 14-15

Chemical composition for carbon steel as specified in 1.3. No special tests required.

25.0 Tie Plug Driver— Plan No. 16

Material as shown on plan. No special tests required.

26.0 Track Chisels— Plan No. 17

See percussion tools.

27,0 Round Track Punch— Plan No. 19

See percussion tools.

28.0 Track Gage— Plan No. 20

Material as shown on plans. No special tests required.

29.0 Track Gage with Wood Rod— Plan No. 20-A

Material as shown on plans. No special tests required.

30.0 Track Shovel— Plan No. 21

30.1 Scope and Design

This specification covers the welded or riveted type and the solid shank type with either wood, malleable iron, combination wood metal, or user approved composition handle tops. Dimension shall conform to plans, which are made part of this specification. A variation of Vi in. more or less from the dimensions shown on the plan for the length of the strap or shank and handle will be allowed. A variation of % in. more or less from the dimensions shown on the plan for the width or length of the blade will be allowed, but the total variation in the overall length of shovels shall not exceed V2 in. more or less of the dimensions shown on the plan.

30.2 Materials

Blades shall be of carbon or alloy steel, with a Rockwell (Re) hardness for carbon steel of 45 to 50.

Carbon steel blades shall have a thickness of not less than No. 13 gage and alloy blades shall be not less than No. 14 gage U.S. Standard, the gage to be measured at the point where the hardness is taken. For welded or riveted types, the straps shall be welded or riveted to the blade.

30.3 Handles and Tops

This specification covers either wood, malleable iron, combination wood metal, or user approved composition handle tops. Wood handles shall be made of ash and shall conform to Grade AA and be in accordance with the general Specifications for Handles for Track Tools.

30.4 Tests

One shovel from each lot of 10 dozen or less shall be selected and metal straps (curved to fit the contour of the handle) shall be clamped to the upper and lower parts of the handle, after which the shovel shall be placed in a prying position, supported at the end of the blade by clamps and shall be capable of sustaining a load of 200 lb. suspended from the end for a period of 2 minutes without showing any permanent set, fracture or distortion.

Alloy steel shovels which have been given heat treatment to insure uniformity in hardness shall be subject to shock test to insure against brittleness. The test shall be made by forcibly striking the blade of the shovel with a hand hammer at several places when placed on an anvil.

Proposed Manual Changes 15

31.0 Ballast Fork— Plan No. 22

31.1 Scope and Design

The dimensions shall conform to the plans, which are made part of this specification. The total variation in the overall length of the forks shall not exceed Vi in. more or less of the dimensions shown on plan.

31.2 Material

Forks shall be made of high grade carbon steel. Tines of forks shall show Rockwell (Re) har- ness of 35-45. Straps shall be 0.04 U.S. Standard gage steel.

31.3 Handles

This specification covers either wood, malleable iron, combination wood metal, or user ap- proved composition handle tops. Wood handles shall be made of ash and shall conform to Grade AA and be in accordance with the general Specifications for Handles for Track Tools.

32.0 Track Tool Handles— Plan No. 25

See Specification For Ash And Hickory Handles For Track Tools for material requirements. No special tests required.

33.0 Scoop— Plan No. 26

33.1 Scope and Design

This specification covers the welded or riveted type and the solid shank type with either wood, malleable iron, combination wood metal, or user approved composition handle tops. Dimension shall conform to plans, which are made part of this specification. A variation of Vi in. more or less from the dimensions shown on the plan for the length of the .strap or shank and handle will be allowed. A variation of Vi in. more or less from the dimensions shown on the plan for the width or length of the blade will be allowed, but the total variation in the overall length of scoops shall not exceed '/2 in. more or less of the dimensions shown on the plan.

33.2 Materials

Blades shall be of carbon or alloy steel, with a Rockwell (Re) hardness for carbon steel of 45 to 50.

Carbon steel blades shall have a thickness of not less than No. 13 gage and alloy blades shall be not less than No. 14 gage U.S. Standard, the gage to be measured at the point where the hardness is taken. For welded or riveted types, the straps shall be welded or riveted to the blade.

33.3 Handles and Tops

This specification covers either wood, malleable iron, combination wood metal, or user approved composition handle tops. Wood handles shall be made of ash and shall conform to Grade AA and be in accordance with the general Specifications for Handles for Track Tools.

33.4 Tests

One scoop from each lot of 10 dozen or less shall be selected and metal straps (curved to fit the contour of the handle) shall be clamped to the upper and lower parts of the handle, after which the shovel shall be placed in a prying position, supported at the end of the blade by clamps and shall be capable of sustaining a load of 200 lb. suspended from the end for a period of 2 minutes without showing any permanent set, fracture or distortion.

Alloy steel scoops which have been given heat treatment to insure uniformity in hardness shall be subject to shock test to insure against brittleness. The test shall be made by forcibly striking the blade of the scoop with a hand hammer at several places when placed on an anvil.

16 Bulletin 760 — American Railway Engineering Association

34.0 Aluminum Track Level And Gage — Plan No. 27

Material as shown on plans. No special tests required.

35.0 Scythe— Plan No. 28

No special tests required.

36.0 Snath— Plan No. 29

Material as shown on plans. No special tests required.

37.0 Spot Board— Plan No. 30

Material as shown on plans. No special tests required.

38.0 Rail Tongs for use with crane — Plan No. 31

Material as shown on plans. In the manufacture of the rail tongs. Section 8.6, Nondestructive Test Requirements will be adhered to.

39.0 Track Spike Lifter— Plan No. 32

See percussion tools.

40.0 Drive Spike Extractor Socket Wrench — Plan No. 33

No special tests required.

41.0 Rail Thermometer— Plan No. 34

Material as shown on plans. No special tests required.

42.0 Nut Cutter— Plan No. 35

See percussion tools.

43.0 Hot Cutter (3 Pound)— Plan No. 36

See percussion tools.

44.0 Hot Cutter (5 Pound)— Plan No. 37

See percussion tools.

45.0 Drift Pin (Short)— Plan No. 38

See percussion tools.

46.0 Drift Pin (Long)— Plan No. 39

See percussion tools.

47.0 Spiking Tool— Plan No. 41

See percussion tools.

48.0 Switch Clip Wrenches— Plan No. 43

Chemical composition for carbon steel as specified in 1.3. If requested by the purchaser, Section 8.6, Nondestructive Test Requirements will be adhered to.

Proposed Manual Changes

17

	PLANS FOR TRACK TOOLS (1997)
Plan		Grade of
Number	Description	Steel		Hardness
1-62	Clay Pick	Carbon or	Alloy	425-500 BHN
2-62	Tamping Pick	Carbon or	Alloy	425-500 BHN
3-83	Spike Maul	Alloy		51-55 Re
4-62	Track Wrenches	Carbon		375-450 BHN
5-62	Lining Bars	Carbon		300-375 BHN
6-62	Rail Tongs	Carbon
7-93	Tie Tongs	Carbon or	Alloy
8-93	Timber Tongs	Carbon or	Alloy
9-94	Spike Puller	Carbon		375-450 BHN
10-97	Rail Fork	Carbon		275-350 BHN
11-97	Claw Bar	Carbon		300-375 BHN
12-62	*Track Adz	Carbon or	Alloy	375-450 BHN
12-A-62	*Carpenters Adz	Carbon or	Alloy
13-83	Double Faced Sledge	Alloy		5 1 -55 Re
14-62	Chisel End Tamping Bar	Carbon		425-500 BHN
15-62	Spear End Tamping Bar	Carbon		425-500 BHN
16-62	Tie Plug Driver	Carbon
17-83	Track Chisel	Alloy		44-48 Re (Head)
19-83	Round Track Punch	Alloy		44-48 Re (Head)
20-62	Track Gage — Pipe Center	See Plan
20-A-62	Track Gage — Wood Center	See Plan
21-62	Track Shovels	Carbon or	Alloy	45-50 Re
22-62	Ballast Forks	Carbon		35-45 Re
25-83	Track Tool Handles
26-62	Scoop	Carbon or	Alloy	45-50 Re
27-80	Aluminum Combination Track Level And Gage (Insulated)
28-62	Scythe	See Plan		54-58 Re
29-62	Snath	See Plan
30-62	Spot Board	See Plan
31-97	Rail Tongs For Use With Crane (Type 1 And 2)	See Plan
32-83	Track Spike Lifter	Alloy		44-48 Re (Head) 44-48 Re (Claw)
33-83	Drive Spike Extractor Socket Wrench	Carbon		300-350 BHN
34-71	Rail Thermometer
35-83	Nut Cutter	Alloy		44-48 Re (Head) 56-60 Re (Point)
36-83	(3 lb.) Hot Cutter	Alloy		44-48 Re (Head) 56-60 Re (Point)
37-83	(5 lb.) Hot Cutter	Alloy		44-48 Re (Head) 56-60 Re (Point)
38-83	Drift Pin (Short)	Alloy		44-48 Re (Overall)
39-83	Drift Pin (Long)	Alloy		44-48 Re (Overall)
41-94	Spiking Tool	Alloy		44-48 Re (Head) 52-56 Re (Point)
43-97	Switch Clip Wrench	Carbon		375-450 BHN
*When specif	led, the small eyed track tools will be furnished with AREA handles. The handles are

to be properly fitted and wedged.

18

Bulletin 760 — American Railway Engineering Association

Page 5-6-27. Insert revised Plan 10, Rail Fork.

PLAN 10 - 97 - AREA RAIL FORK

Proposed Manual Changes

19

Pase 5-6-28. Insert revised Plan 11, Claw Bar.

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PLAN 11-97 AREA CLAW BAR

20

Bulletin 760 — American Railway Engineering Association

Page 5-6-39. Insert revised Plan 31, AREA Rail Tongs for Use with Cranes (Type 1 and Type 2).

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PLAN 31 -97 AREA RAIL TONGS FOR USE WITH CRANES (TYPE 1)

Proposed Manual Changes

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PLAN 31-97 AREA RAIL TONGS FOR USE WITH CRANES (TYPE 2)

Bulletin 760 — American Railway Engineering Association

Page 5-6-46. Add new Plan 43, AREA Switch Clip Wrench.

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PLAN 43 - 97 - AREA SWITCH CLIP WRENCH

Specialists In keeping Bridges In service

•TIMBER •STEEL •CONCRETE

Over 40 years of railroad experience. Inspect. . . Repair. . . Treat. . . Strengthen

RAILROAD DIVISION P O Box 8276 • Madison, Wisconsin 53708 608/221-2292 • 800/356-5952

WE'RE THE BRIDGE PRESERVERS

URVE

CONQU EROI

Rocia prestressed concrete ties conquer the curves. They provide a stiffer track modulus, improved lateral stability and gauge control, increased rail life, greater locomotive fuel economy, and significantly lower maintenance costs.

Two North American manufacturing plants to serve you. Unsurpassed quality and durability. Go with the leader in North American prestressed concrete ties. Call:

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701 West 48th Avenue • Denver, Colorado 80216 (303) 296-3500 • Fax (303) 297-2255

268 East Scotland Drive • Bear, Delaware 19701 (302) 836-5304 • Fax (302) 836-5458

23

Engineered To Handle Higher Speeds, Tighter Turns And Heavier Loads, Today's Wood Crossties Offer You Superior Cost And Performaince Advantages.

Maybe not. Maybe even tougiier wlien you consider ttie tremendous variables that track engineers contend with. Materials with differing physical properties and maintenance needs. Track structures that must stand up to an enormous range of loadings and speeds, for long periods of time, in all types of weather, over all kinds of terrain. Enter yet another factor — high-speed passenger trciffic — and the complexity increases.

Fortunately, there is a proven performer you can count on to handle your toughest demands. The treated wood crosstie.

Pre-engineered by nature and enhanced by man, the wood crosstie is a marvel of natural science and applied technology.

Concrete Cuidence That UJood Is Vour Best Choice.

For 150 years, the wood tie has taken everything that man and nature have dished out. Steep grades. Brutal environments. High speeds. Heavier axle loads. Tighter curves.

Through it all, resilient wood has been and continues to be the material of choice for durability, economy and strength. No other material matches wood's value on freight and passenger lines.

And innovations in hardware, installation methods and wood preservation have taken a good thing and made it even better By improving gage retention. Minimizing maintenance. And increasing tie life.

Building track structures is decidedly complex. But choosing the best crosstie isn't exactly "rocket science". Just say wood.

m

Railway Tie Association

Wood crossties. Something to build on.

115 Commerce Drive • Suite C Fayetteville,GA 30214

Phone (770) 460-5553 Fax (770) 460-5573

Proposed Manual Changes 25

Proposed 1997 Manual Revisions to Cliapter 8 — Concrete Structures and Foundations

Part 21 — Inspection of Concrete and Masonry Structures

Page 8-21-1. Insert revised Part 21, Inspection of Concrete and Masonry Structures, including the Effects of Fire in a new Commentary.

Part 21 — Inspection of Concrete and Masonry Structures

21.1 General

21.1.1 All concrete and masonry structures and components should be given thorough, detailed inspections at scheduled intervals. For timber and steel components, refer to Chapter 7 and Chapter 15, respectively. The depth and detail of the inspection should be based on the condition and age of the structure, and traffic type and tonnage in order to determine that the physical condition of each structure is suitable for the imposed loading. A record of physical conditions should be kept.

21.1.2 A special inspection may be required when the structure is subjected to abnormal con- ditions which may affect the capacity of the structure such as: floods, storms, fires, earthquakes, col- lisions, overloads and evidence of recent movement. Refer to commentary for information related to inspection of fire damaged concrete.

21.1.3 The inspector should review prior inspection reports before making the inspection. Previously noted defects should be examined in the field and any changes in conditions recorded. Field book, sketch pad, inspection form, camera, monitoring gages, etc. should be used to record the inspec- tion data. Appropriate personal safety equipment should be employed throughout the inspection.

21.2 Reporting of Defects

2 1 .2. 1 When the inspector finds defects that appear to be of such a nature as to make the pas- sage of traffic unsafe, the condition should immediately be reported. After steps have been taken to protect traffic, the train dispatcher and appropriate officers should be notified, consistent with estab- lished policies, recommending a speed limit and briefly describing the conditions which prompted the action. The inspector should follow this immediately with a report so that a detailed investigation and recommendation for repair can be made.

21.2.2 Upon completion of the inspection, a written record covering the inspection should be forwarded to the engineer or other officer in charge of maintenance. Upon receipt of the report, a review should be made to determine the need for remedial action.

21.3 Inspection

21.3.1 The inspection of concrete and masonry structures should be carried out in a methodi- cal manner. Of primary importance in all structures is evidence of distress, misalignment, deflection, settlement, cracks, and general deterioration. Evidence of deterioration of concrete such as width and length of structural cracks, size and location of spalling and .scaling, and location and extent of water- saturation of concrete should be recorded.

21.3.2 The inspector should report indications of failure in any portion of the structure and any conditions which could contribute to a future failure.

2 1 .3.3 If practical, the inspector should observe the structure during passage of a train, so that the effects of vibration, sidesway and deflection may be noted.

21.3.4 Reference points should be established for monitoring misalignment, deflection, settle- ment, and cracks. The amount of tilt, separation between components, width and length of cracks, efflo- rescence and rust-staining and other measurements necessary for future checking should be recorded.

26 Bulletin 760 — American Railway Engineering Association

21.3.5 The inspection should include the structure and all related features. The following addi- tional items should be covered in detail.

21.3.5.1 Track

The inspector should note the alignment, profile and surface of the track on the structure, its approaches and bridge ends. Any irregularities in line or surface should be noted along with their magnitude, location and any other information that may indicate the cause of the irregularities. Depth of ballast and condition of ballast, ties and hardware should be noted. Line swings may be an indi- cation of pier movement. Sags in the track over the structure may indicate settlement.

21.3.5.2 Site and Crossing

a) Where a structure cros.ses over a waterway, the inspector should note the condition and alignment of the waterway. The condition of the slopes and any slope protection (such as riprap) should be noted along with any indication of debris accumulation. The inspector should note any indication of damage from marine collision, ice or debris.

b) Where scour is possible, the channel bottom at piers and abutments should be checked by sounding, probing or other means.

c) Where a structure carries tracks over a roadway or another track, the inspector should note any indication of collision damage from high or wide loads. Roadway clearances should be measured and signage verified for accuracy.

21.3.5.3 Foundations, Piers and Abutments

a) The inspector should note any settlement and/or rotation of foundations, piers, abutments or their component parts. Reference points should be established for monitoring of structural movement if appropriate.

b) The type of foundation and type and condition of material used in the various structural components should be noted. Location and extent of exposed or corroded reinforcing bars should be reported. The condition of the structure at the bridge seats, bearings and near the waterline should also be investigated.

c) Crack width, orientation and location should be noted. Widths and lengths of structural cracks should be marked and dated to monitor crack progression. On masonry structures note cracked, shifted, or missing stones, and condition of mortar.

d) Location, size and description of unsound areas, spalling, scaling or other deterioration should be noted.

e) Condition of retained fill, drainage and slope protection at abutments should be inspected. Water-saturated masonry or concrete and extent of efflorescence and rust-staining should be noted. Check weepholes and drains for clogging.

21.3.5.4 Pile and Pile Bents

a) Inspection of piling and pile bents should be in general conformance with Article 21.3.5.3. For timber and steel components, refer to Chapter 7 and Chapter 15, respectively.

b) Alignment and condition of piling should be recorded. Impact damage from debris, vessels or vehicles should also be noted.

c) Condition of piles should be investigated for .soundness. Loss of section and cracking should be noted. These may be especially severe in a marine environment, particularly in the tidal zone.

d) Connections between cap and piling should be inspected.

e) Bracing members and their connections should be inspected.

Proposed Manual Changes 27

21.3.5.5 Underwater Inspections

The need and frequency for underwater inspections should be evaluated for every structure hav- ing submerged components. These inspections should identify the channel bottom conditions and presence of any scour, extent of foundation exposure and any undermining, and all deterioration and damage below water.

a) Divers should be experienced in the inspection of bridges.

b) Inspection data should be recorded by written description, sketches, reports, photography and/or video.

c) During high water events when scour conditions may be expected, channel activity should be monitored, which may include the use of sonar readings, until inspections can be made.

21.3.5.6 Retaining Walls

a) The inspector should note any settlement and/or rotation of retaining walls. Changes in wall alignment or cracks in earth embankment which parallel the wall should be noted.

b) Concrete inspection should be in general conformance with 21.3.5.3.

c) Condition of retained fill and drainage at walls should be inspected. The extent of water-sat- urated concrete and exposed or corroded reinforcing bars should be recorded.

21.3.5.7 Slabs and Beams

a) Inspector should note if prestressed or conventionally reinforced concrete is used in the struc- ture. Method of construction, cast-in-place or precast, simple or continuous, should also be indicated.

b) Any cracks that open and close under traffic, diagonal cracks near supports, or wide or numerous cracks in any location should be reported immediately to the proper authority. Acute cor- ners of skewed bridges should be examined for cracking.

c) Structural members should be inspected for excessive deflection or misalignment.

d) Curbs, ballast retainers, walkways and handrails should be inspected, noting the condition as to soundness and security of fastening devices. Soundness, uniformity and condition of bearings and bearing areas should also be noted. Areas exposed to drainage should be checked for spalling and cracking.

21.3.5.8 Box Girders

a) Type of box construction (precast, segmental, pre-tensioned, post-tensioned, simple or con- tinuous spans) should be recorded.

b) General inspection guidelines should be as outlined in 21.3.5.7. Top flange, bottom flange and web walls should be inspected when accessible. Chamfers of boxes should be inspected for cracking which may extend along the sides or bottom of the girders.

c) Shear transfer devices between adjacent box girders should be inspected, where accessible. Condition of grout, hardware, tie rods, and other materials used in tying together adjacent box gird- ers should be noted. Evidence of differential box deflections or misalignments should be recorded.

d) Condition of void drain holes and evidence of leakage between adjacent boxes should be noted.

21.3.5.9 Arches

a) Type of arch construction, such as segmental, open spandrel, closed spandrel, single or mul- tiple span should be noted. Shape of arch span (circular, elliptical or parabolic) should be recorded, if known. Type and general condition of material (brick, stone, mortar or concrete) should also be recorded.

Bulletin 760 — American Railway Engineering Association

b) Arch foundations should be investigated for settlement, shifting, scour and undermining.

c) Arch ribs and bearing areas of arches at springings should be inspected for loss of cross sec- tion due to spalling or cracking.

d) Open spandrel columns should be inspected with particular attention to areas near the inter- face with the arch rib and cap.

e) Arch ribs connected with .struts should be inspected for diagonal cracking due to torsional shear.

f) Floor systems of open spandrel arches and closed spandrel arches with no till material should be inspected as outlined in 21 .3.3.7.

g) Inspect areas exposed to drainage and seepage for deteriorated and contaminated areas. For closed spandrel arches, note if weepholes are working properly.

21.3.5.10 Structural Protection

Structural protection devices including crash walls, cellular dolphins, pile clusters, sheer fences, floating sheer booms, anchored pontoons, fender systems, navigation lights and warning mechanisms should be inspected as part of the scheduled inspection of their related foundation or substructure ele- ment. The inspection should identify all deterioration, damage, displacement, misalignment, insta- bility, and any other detrimental conditions which would inhibit these devices from protecting the structure or cause them to create an obstruction. All submerged portions of structural protection devices should be inspected underwater based on the recommendations set forth in Article 21.3.5.5. The inspection of structural protection devices should also note any aspects which may present a haz- ard to navigation, and identify the necessary measures to correct the situation.

21.3.5.11 Culverts

a) Inspector should note any settlement, variations in cross-sectional shape and misalignment along the horizontal axis of a culvert. All joints between end treatments and within the culvert itself should be examined for differential movement, and all transverse or longitudinal cracking within a culvert should be noted. Look for holes appearing in the track structure as an indication of open cul- vert joints.

b) A culvert should be inspected for any scour or undermining at either end. Any embankment damage around the culvert openings and debris or vegetation within the culvert should be noted. All submerged portions of a culvert should be inspected underwater based on the recommendations set forth in Article 21.3.5.5.

c) Inspection of a concrete or masonry culvert in general should be in conformance with Article 21.3.5.3

21.3.5.12 l\innels

a) Important features of a tunnel might be obscured by a shield or lining, therefore the inspec- tor should review plans, if available, prior to the inspection. Note the structural configuration, provi- sions for drainage, ventilation and lighting. Note if secondary passageways that would provide addi- tional access for inspection are present.

b) Concrete inspection should be in general conformance with 2 1 .3.5.3. In exposed masonry con- struction, make special note of bulges in walls and displacement, shifting or loss of masonry or mortar.

c) Walls should be inspected for indications of water leakage or ice buildup. The condition and effectiveness of drainage systems should be noted.

d) Note whether ancillary systems for lighting, ventilation, and fire prevention are in working order, if discernible.

Proposed Manual Changes 29

e) The accumulation of trash or foreign debris or the blockage of safety niches should be noted.

0 Any new construction above or adjacent to the tunnel should be noted.

g) Horizontal and vertical clearances should be verified. Items causing changes in clearance should be noted.

h) The inspector should note the alignment, profile and surface of the track and clearance of the tunnel.

21.3.6 Bibliography

Bridge Inspection Seminar Manual, American Railway Bridge and Building Association, Atlanta, Georgia, February 22-24, 1993.

Bridge Inspector's Training ManuaI/90, FHWA-PD-9I-0I5, U.S. Department of Transporta- tion, Federal Highway Administration, May, 1991

Underwater Inspection of Bridges, FHWA-DP-80- 1 , Federal Highway Administration, Novem- ber, 1989.

Part 21 -Commentary Inspection of Concrete and Masonry Structures

C21.1.2 Guidelines for Evaluating Fire Damaged Concrete Railway Bridges

C21. 1.2.1 General

Concrete structures exposed to fire may experience a permanent loss of strength, formation of structural cracks, surface spalling, and reinforcing damage. However, concrete structures exposed to fire generally perform well and usually are repairable. The heat conductivity of concrete is low and thus heat from a fire is usually confined to shallow depths. The extent of structural damage is related to the intensity and duration of the fire, and the mass and details of the concrete structure.

The exposure of concrete to a temperature of 300°C (572°F) is significant for two reasons:

• Below this temperature the effects of heat on concrete are likely to be insignificant.

• Above this temperature concrete coloration changes may indicate permanent damage.

Water directed on hot concrete may cause spalling, crack developinent and the embrittlement of steel. Fire fighting efforts should be directed to extinguishing the combustible material and not cooling the structure.

Traffic should not cross the structure if significant deflection or distortion is noted or if there are reasons to doubt that adequate strength remains.

C21. 1.2.2 Inspection

Prior to the inspection of a damaged concrete structure, it should be determined whether the site is safe for entry.

Damage may include the deflection of concrete beams and slabs, di.stortion of columns, crack- ing, spalling and un.sightly appearance.

Inspection observations should include looking for and measuring any unusual component deflection, recording the location and extent of structural cracks, spalls and exposed reinforcing. Fire exposed surfaces should be mapped to indicate those areas having structural and cosmetic damage. If fire exposed surfaces exhibit colorations of pink, white or buff, those surfaces should be mapped and color noted. Surfaces may need to be cleaned of soot to make these observations.

30 Bulletin 760 — American Railway Engineering Association

Information concerning the combustible material, duration, intensity indicators and method for extinguishing should be obtained from eyewitnesses or other reliable sources for assistance in eval- uating the damage. Although any concrete coloration from the fire may provide sufficient informa- tion concerning the intensity of the fire, if coloration is not evident, to a lesser degree other materi- als associated with the fire site may have melted and may provide some indication of the fire intensity; such as: lead 327°C (62 IT), plastics 300-450°C (572-842°F), glass 400-500°C (752-932°F), aluminum 660°C (I2I8°F) and copper 1083°C (IQSTF). Other information concerning the original concrete strength, age, reinforcing details and types of aggregates may be obtained from structural plans, specifications and construction records.

C21. 1.2.3 Evaluation

Generally, all concrete that has coloration changes (pink, white, bufO is considered damaged. The pink coloration 300°C (572°F) experienced by heating concrete is the formation of ferrous salts and is more pronounced in concrete with siliceous aggregates. At approximately 600°C (IIIOT), concrete may have a whitish coloration from the hydration of lime. At 900°C (1650°F) the coloration may be grey-buff.

Indications of possible structural damage may be evident by visual examination, but the extent of damage will require tests and analysis. Evaluation tools for testing include: surface hammer sound- ing, impact hammers, coring and/or drilling and pulse-echo non-destructive testing. Sounding the concrete surface with hammers may be sufficient to determine if there is any internal concrete delam- ination. Calibrated impact hammers can give direct measurements of the concrete compressive strength and may be used on sound and unsound concrete for quick strength comparisons. Coring will assist in determining the depth of damage and corings destructively tested will ascertain accurate compressive strength. A petrographic analysis of cored samples will give a detailed analysis of the concrete condition but the analysis is time consuming. Pulse-echo testing can give a rapid and accu- rate determination of internal concrete conditions relative to micro-cracking and bond loss. Additional testing may be needed for prestressed and post-tensioned concrete.

Concrete strength decreases as temperature is increased and further decreases on cooling as a result of micro-cracking. Approximately 75% residual strength remains in most concrete after expo- sure to fire. This loss may be offset by excess residual strength of mature concrete. Internal induced stresses from differential heating may result in the formation of cracks. Young concrete may experi- ence more damage than mature concrete due to larger amounts of internal moisture that may convert to steam and increase internal tensile stresses.

Damage may result from aggregate spalls due to physical or chemical changes. Explosive spalling may occur from the release of tensile stresses by the formation of steam within aggregates. Slough-off or the detachment of layers of concrete may occur where reinforcement is restrained. Igneous aggregates (granite, basalt) generally perform well when exposed to fire, carbonate aggre- gates (limestone) perform well to about 700°C ( 1290°F), and siliceous aggregates (quartz) do not per- form well due to expansion and cracking.

The absence of deflection or distortion in any element may indicate that the steel was not damaged. Reinforcing steel usually recovers in strength unless exposed to temperatures over 600°C (lllOT). Anchorages of post-tensioned members may require special evaluation. The tension in pretensioned steel or post-tensioned ducts exposed by spalling should generally be assumed to be zero. Prestressed mem- bers may suffer substantial relaxation losses, additional to those allowed by normal design. Low relax- ation strands may have improved fire performance. At 300°C (572°F) the residual bond strength is approximately 85% and at 500°C (932°F) the bond strength is approximately 50% of initial bond. Bond strength losses of epoxy coated reinforcing steel subjected to fire may require special evaluation.

Resins used in construction bonding of concrete elements and in repairs may not perform well in the presence of elevated temperatures.

Proposed Manual Changes 3 1

Hydrochloric acid fumes occurring in fires involving PVC and other plastic ducts may react with hardened cement paste to form calcium chloride which may constitute a hazard to the rein- forcement. A silver/chromate test can confirm the presence of calcium chloride ions.

C21.1.2.4 Repairs

Repair procedures, as applicable, are outlined in Part 14.

Pulse-echo or other non-destructive testing may be used to confirm that all damaged concrete is removed and can be u.sed to confirm proper bonding of new concrete to old concrete and bonding to reinforcement.

C21.1.2.5 Bibliography

Evaluation and Repair of Fire Damage to Concrete, AC! SP-92, American Concrete Institute, Detroit, Michigan. 1986

Fire Safety of Concrete Structures, ACI SP-80, American Concrete Institute, Detroit, Michigan, 1983

Guide for Determining the Fire Endurance of Concrete Elements, ACI216R-89, American Concrete Institute, Detroit, Michigan, 1989

Reinforced Concrete Fire Resistance, CRSl Engineering Practice Committee, Concrete Reinforcing Steel Institute, Chicago, Illinois, 1980.

C21.3.1 Inspection — Commentary

There are many common defects that occur on concrete bridges. The following definitions are provided as a guideline for consistency in reporting of defects.

Abrasion — Abrasion damage is the result of external forces acting on the surface of the con- crete member. Erosive action of silt-laden water running over a concrete surface and ice flow in rivers and streams can cause considerable abrasion damage to concrete.

Cold joint displacement or deterioration — Unbonded concrete resulting from intended sepa- rate concrete placement or by lack of consolidation.

Cracking — A crack is a linear fracture that may extend partially or completely through the con- crete member. When recording cracks, the inspector should describe the type, width, depth, length, direction, location and appearance of the crack as appropriate for the inspection.

Delamination — Delamination occurs when layers of concrete .separate at or near the level of the top or outermost layer of reinforcing steel. The major cause of delamination is expansion of cor- roding reinforcing steel. Delaminated areas can generally be identified by a hollow sound when tapped with a hammer.

Efflorescence — Efflorescence is a white deposit on concrete cau.sed by crystallization of solu- ble salts (calcium chloride) brought to the surface by moisture in the concrete.

Honeycombs — Honeycombs are hollow spaces or voids that may be present within the con- crete. Honeycombs are caused by improper consolidation dunng construction, resulting in the segre- gation of the coarse aggregates from the fine aggregates and cement paste.

Pop-Outs — Pop-outs are conical fragments that break out of the surface of the concrete leav- ing small holes. Generally, a shattered aggregate particle will be found at the bottom of the hole, with a part of the fragment still adhering to the small end of the pop-out cone.

Scaling — Scaling is the gradual and continuing loss of surface mortar and aggregate over an area. When reporting scaling, the inspector should note the location of the defect, the size of the area, and the depth of penetration of the defect.

32 Bulletin 760 — American Railway Engineering Association

Spalling — A spall is a roughly circular or oval depression in the concrete. Spalls result from the separation and removal of a portion of the surface concrete, revealing a fracture roughly parallel to the surface. Spalls can be caused by corroding reinforcement and friction from thermal movement. Reinforcing steel is often exposed. When reporting spalls, the inspector should note the location of the defect, the size of the area, and the depth of the defect.

C21.3,5.2 Site and Crossing — Commentary

The inspector should note any changes in the alignment of a waterway both upstream and downstream and the resulting effect that they may have on the structure. A major change in the align- ment of a waterway may place it outside the spans intended for the crossing.

Sedimentation deposits may fill scour holes after high water events. Underwater investigations may be required as per €21. 3. 5. 5.

Structures located downstream of spillways or locks may be subject to increased scour potential.

C21.3.5.3 Foundations, Piers and Abutments — Commentary

Concrete and masonry structures are placed on foundations of earth, piling, cribbing, rock or other similar material. Cracks may be evidence of settlement which has occurred during consolida- tion of the foundation. Settlement may occur without cracking. Noticeable changes in track surfaces and alignment, plumbness or elevation may indicate foundation settlement. Changes in backwall alignment or cracks in the earth embankment parallel to the backwall may indicate movement. Constant wetting may indicate swelling, premature loss of mortar, deterioration of facing or exces- sive water pressure behind backwalls. Exposure of timber mats or untreated timber piling may lead to rapid deterioration of the timber.

C21.3.5.5 Underwater Inspections — Commentary

In evaluating the need for an underwater inspection, consideration should be given to type and depth of foundation, depth of water, normal and peak flow rates, nature of channel bottom and sus- ceptibility to and history of scour, type of aquatic environment, typical extent of drift and ice accu- mulation, and amount and type of watercraft traffic. The inspections should be performed with suf- ficient frequency to provide early detection of any detrimental conditions, and between inspections, the measuring of water depths should be considered to monitor channel bottom activity. In the event of a high water and/or flow occurrence, an excessive accumulation of ice or drift, a watercraft colli- sion, a significant change in channel bottom configuration, or any submerged component movement, consideration should be given to performing an emergency inspection as soon as conditions will safely permit.

C2 1.3.5.6 Retaining Walls — Commentary

In addition to structural deficiencies, retaining wall failures may result from:

(1) Softening of the supporting material by moisture.

(2) Overloading of the embankment behind the wall.

(3) Scour or erosion beneath the foundation.

(4) Expansive backfills.

(5) Hydrostatic pressure behind wall.

Cracks in the earth embankment which parallel the wall may be signs of wall movement.

C21.3.5.7 Slabs and Beams — Commentary

b) Transverse cracks in the bottom of simple span slabs and beams can indicate overload, par- ticularly if cracks open and close during passage of a train. Hairline cracks on the tops of simple span

Proposed Manual Changes 33

prestressed beams are generally due to shrinkage of the concrete. Hairline cracks in the top or bot- tom of simple span reinforced concrete slabs and beams are generally not significant. Diagonal cracks running up the sides of the slab or beam from near the supports may indicate excessive shear stress in the member or the beginning of shear failure.

Transverse cracks in the top of continuous beams over support locations or in the bottom of continuous beams within the span can indicate overload.

c) Sagging or excess deflection may indicate a loss of prestress. Loss of prestress may be caused by strand slippage, which may be visible at the ends of beams.

d) End spalling can lead to a loss of bond in the prestressing tendons. Note any deterioration that has exposed or damaged prestressing tendons.

C21. 3.5.8 Box Girders — Commentary

b) Horizontal or vertical cracks in the top of girder ends are probably due to stresses created at the transfer of prestressing forces. Flexural cracks in the lower portion of the girders, particularly at mid-span, may indicate a problem resulting from overload or loss of prestress.

c) Individual girder deflection under live load may indicate shear keys between boxes have been broken and that boxes are acting independently of each other.

C21.3.5.9 Arches — Commentary

a) A true arch has an elliptical shape and functions in a state of pure compression. Many arches are not elliptical and resist loads by a combination of axial compression and bending moment.

c) Changes in alignment, sags in the arch crown, bulges in the sidewalls, transverse and longi- tudinal cracks and expansion joint failures may be signs of settlement, overload or impending arch failure.

d) The area between the arches and the deck is called the spandrel. Open spandrel concrete arches receive traffic loads through spandrel bents which support a slab or tee beam floor system. Horizontal cracks in spandrel columns within several feet of the arch indicate excessive bending in the column, which may be caused by overloads and differential arch rib deflection.

g) The spandrel area in closed spandrel arches is typically occupied by fill retained by vertical walls. Surface water should drain properly and not penetrate the fill material.

C21.3.5.11 Culverts — Commentary

a) Horizontal alignment of a culvert can be inspected by sighting along one of the culvert walls. Sag in the culvert axis may be identified by a location of sediment build-up on the culvert floor. Spalls or cracking in the vicinity of a joint may be a sign of movement at the joint. Both longitudi- nal and transverse cracking may be an indication of differential settlement. Longitudinal cracks can also be caused by a structural overloading of the culvert.

b) Insufficient hydraulic capacity, either by design or due to obstructions, may cause upstream ponding and lateral flow movements which can erode the embankments and supporting material around the culvert end treatments. Culverts often convey short-term, high volume flows, and conse- quently, all culverts should be carefully inspected for scour and undermining. Tipping, cracking or separation of the headwalls, wingwalls or apron may indicate the presence of undermining. For arch and frame type culverts with earthen floors, undermining beneath the wall foundations along their full length should also be investigated.

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Proposed Manual Changes 35

Part 24— Drilled Shaft Foundations

Page 8-24-2. Insert revised Part 24, Drilled Shaft Foundations, as follows.

24.1 General

24.1.2 Scope

This specification covers the description and general aspects of design, installation, inspection and testing of drilled shafts, also frequently referred to as drilled caissons, drilled piers, or bored piles.

This specification is intended to serve as guidelines in developing specific designs and con- struction specifications on a project basis.

For the purpo.se of this specification, the minimum diameter of these units shall be 30 inches (0.75 meter). Drilled shafts with smaller diameters have been constructed, but are not included in this specification.

This specification relates primarily to single vertical drilled shafts.

Factors to be used in modifying the capacities of single drilled shafts for determination of the capacity of a group of drilled shafts which support a common rigid cap are included elsewhere in this specification.

The use of battered drilled shafts to accommodate lateral loads by the horizontal component of the shaft axial resistance is not recommended and is not addressed by this .specification. Lateral loads applied to drilled shafts are to be resisted by the effect of soil/rock interaction between the shaft and ground.

24.1.2 Purpose and Necessity

Drilled shafts are used to transmit loads through soils of poor bearing capacity into rock or soil formations having adequate bearing capacity. Generally, single drilled shafts have load capacities much larger than piling due to their larger size and capability of belling to increase the bearing area without enlarging either the footing or the drilled shaft.

The selection of foundation treatment for a given site should be determined by subsurface con- ditions, and by economic considerations as there is often a choice of several types of foundations for a structure.

24.1.3 Definitions (see Figure I)

Drilled Shaft — A machine and/or hand excavated shaft, concrete filled, with or without .steel reinforcing, for the purpose of transferring structural loads to bearing .strata below the structure.

Protective Casing — Protective steel unit, usually cylindrical in shape lowered into the excava- tion to protect workmen and inspectors from collapse or cave-in of the side wall.

Bell or Underream — An enlargement at the bottom of the drilled shaft made by hand excava- tion or mechanical underreaming with drilling equipment for the purpose of spreading the load over a larger area.

Socket — A shaft of equal or smaller diameter extended into the bearing material.

Toe — Vertical section at bottom of bell.

Permanent Casing — A steel cylinder that is installed for the purpose of excluding soil and water from the excavations. It is used as a form to contain concrete placed for the drilled shaft and remains in place.

Rd'crcncc. Vol. »5. iy84. p.2y.

Latest page con.sisl: I to X. incl. ( iyX4).

36

Bulletin 760 — American Railway Engineering Association

NOMINAL SHAFT DIAMETER (B

I J 1 r]

CASING

60* MIN

-REINFORCING STEEL

BELL DIAMETER

SOCKET DIAMETER

OPTIONAL SOCKET

1. FIGURE IS FOR ILLUSTRATIVE DEFINITION OF DRILLED SHAFT NOMENCLATURE

2 THE NEED FOR OR EXTENT OF CASING IS DEPENDENT ON LOCAL SOIL AND GROUND WATER CONDITIONS.

3. THE NEED FOR AND EXTENT OF REIN- FORCING STEEL SHALL BE AS SPECIFIED BY THE DESIGN ENGINEER.

Figure 1 Drilled Shaft

Temporary Casing— A steel cylinder that is installed for the purpose of excluding soil and water from the excavations. It may also be used as a form for the shaft concrete but is withdrawn as the shaft concrete is placed.

24.1.4 Design Loads

Loading for drilled shafts shall be the design loads from the supported structure without applica- tion of load factors used for Load Factor design procedure. Design loads shall include the following:

Proposed Manual Changes 37

Primary Forces:

Dead Load

Live Load

Centrifugal Force

Earth Pressure

Buoyancy

Negative Soil Friction

Secondary Forces (Occasional): Wind and Other Lateral Forces Ice and Stream Flow Longitudinal Forces Seismic Forces

When drilled shaft foundations are designed for both primary and secondary forces, the allowable load on the drilled shafts may be increased by 23 percent, provided that the size or number of drilled shafts is not less than that required for primary forces alone. In soils where downward movements of surrounding soil relative to the drilled shaft are expected to occur, axial loads shall include negative soil friction forces, acting downward on the drilled shaft. Under special conditions swelling soils can pro- duce upward forces, with fluctuation of the water table, which should also be considered in design.

24.2 Information Required

24.2.1 Field Survey

Sufficient information shall be furnished in the form of profile and cross sections to determine general design and structural requirements. The location of overhead and underground utilities, exist- ing foundations, roads, tracks, or other structures shall be indicated. Records pertaining to high and low water levels and depth of scour shall be provided for stream crossings.

24.2.2 Subsurface Investigation

Foundation material shall be investigated as specified under Chapter 8, Part 22, Geotechincal Subsurface Investigation, in order to determine soil or rock properties, ground water elevations, and any other pertinent conditions.

Where a large portion of the required shaft capacity is to be generated from tip resistance of the shaft or rock .socket, the geotechnical investigation shall be of sufficient scope to permit the deter- mination that the .strata in which the tip is founded is of sufficient depth and .strength to carry the loads to which it is subjected.

Reference is also made to Chapter 8, Part 4.3.1, for additional information.

24.3 Design

24.3.1 General

The design is divided into three basic parts: ( 1 ) transfer of load from the drilled shaft to the rock and/or soil bearing strata; (2) the drilled shaft itself; and (3) the connection between the supported structure and the drilled shaft.

24.3.2 The transfer of Load from the Drilled Shaft to the Rock or Soil Bearing strata.

24.3.2.1 Drilled shafts transfer load to the bearing strata as follows:

a. An end bearing-type drilled shaft transfers essentially all of its load through weaker soils to a layer of soil or rock with adequate bearing capacity.

b. A friction-type shaft whereby the drilled shaft load is transferred to the surrounding material primarily through friction between the shaft wall and the adjacent material.

38 Bulletin 760 — American Railway Engineering Association

c. A combination end bearing and friction-type drilled shaft is a shaft in which some of the load is transferred into the stratum by soil friction and the remainder by end bearing.

24.3.2.2 Lateral Loads and Moinent: When the drilled shaft is subjected to lateral load and moments, as well as axial load, the distribution of soil pressures and the variation of moments and shear in the shaft must be determined.

24.3.2.3 Belled Shafts: Where the bearing strata has insufficient strength to support the load on the ba.se of the shaft, the shaft bottom may be enlarged by belling or underreaming to reduce the pressure by distributing the load over a greater area. Belled shafts shall be used only where the soil/rock in which the bell is placed will not collapse due to the underreaming. Bells are normally unreinforced. The base diam- eter of the bell shall not exceed three times the shaft diameter and the sides shall not be less than 60 degrees from the horizontal. The toe height of bottom edge shall not be less than 6 inches (150 mm).

24.3.2.4 The uhimate axial capacity of a drilled shaft (Q^,,) shall be based on the summation of the ultimate shaft tip capacity and ultimate side resistance capacity minus the weight of the shaft. The allowable shaft capacity shall be the ultimate capacity divided by a factor of safety.

The ultimate shaft tip capacity (Q,) shall be Q^ = qr • A^, where qr is the ultimate unit soil tip resistance determined by geotechnical analysis and A^ is the area of the shaft tip.

The ultimate side resistance (Q,) of the shaft shall be equal to the circumference of the shaft multiplied by the embedment length in a soil layer of uniform unit side resistance (qs) multiplied by qs. The value(s) of qs shall be determined by geotechnical analysis. Where a shaft passes through stratified soil having different values of qs for the various soil type layers, the value of Qs shall be the shaft circumference multiplied by the summation of various q^ values multiplied by the depth of the respective layer. In general, the top five feet of an embedded shaft and a bottom length equal to the diameter of the shaft tip or perimeter of the bell shall be considered as non-contributing to the side resistance of the shaft. Where the drilled shaft is located in scour susceptible areas, the probable depth of scour shall also be deducted when calculating the ultimate shaft side resistance.

Where rock sockets having a diameter equal to or less than the nominal diameter of the shaft are used, the ultimate tip capacity of the shaft shall be equal to the area of the socket tip multiplied by the uniaxial ultimate unit rock capacity. The ultimate socket side resistance shall be the product of the socket circumference, socket embedment and ultimate unit side shear resistance along the socket/rock interface.

Unless an analysis is used which accounts for the load/deflection relationship of the various soil or rock strata encountered, the ultimate capacity of a drilled shaft which utilizes a rock socket shall be based on the sum of the ultimate tip and side resistance capacities of the rock socket only, neglect- ing nominal capacities of the shaft in the soil overburden.

24.3.2.5 Uplift Capacity: The ultimate uplift capacity of a drilled shaft shall be equal to or less than the weight of the shaft plus 0.7 times the ultimate side resistance of the shaft. If belled, the uplift capacity of the shaft may be increased by taking into consideration the reinforcement details of the shaft and bell together with the strength characteristics of the adjacent material.

24.3.2.6 Factors of Safety: For drilled shafts in soil or socketed in rock, a minimum design fac- tor of safety of 2.5 shall be used against bearing capacity failure. A factor of safety of 2.5 shall be used when designing for conditions which produce uplift.

24.3.2.7 Shafts Under Water: Wherever practicable, the drilled shaft shall be designed to per- mit the placing of the concrete in the dry, and for visual inspection of the hole, the bearing strata, and the rock socket.

When it is impractical to dewater the excavation for rock-socketed shafts, the concrete may be placed under water by means of a tremie or pumped concrete and appropriate allowances made in the concrete mix design. The water level shall have reached a static condition before concrete placement begins.

Proposed Manual Changes 39

When concrete cannot be placed in the dry and a thorough visual inspection cannot be made by television or by divers, the Design Engineer shall reduce the allowable bearing and side resistance stress appropriately.

Any free water in belled shafts shall be removed by pumping or bailing, and the bottom rein- spected before placing concrete in the dry.

24.3.3 The Drilled Shaft

24.3.3.1 The drilled shaft is generally designed as a short column for axial loads due to the lat- eral support provided by the soil/rock. In muck or water, slenderness effects of the column must be taken into consideration.

When the drilled shaft is subjected to moment and lateral forces at the connection to the sup- ported structure, the shaft must be designed for bending and shear in addition to axial force. Moment and shear along the length of the shaft must be calculated, and adequate reinforcement provided.

24.3.3.2 The shaft shall satisfy the design requirements of part 2 of this Chapter.

24.3.4 Connection Between Supported Structure and Drilled Shaft

The connection between the drilled shaft and the supported structure (parts above the top of shaft) shall be capable of transferring the design loads, including direct load, shear and moment. This can be accomplished by the following means:

a. When the supported structure at the top of shaft is of concrete, the reinforcing steel cage shall be extended into the cap so that the load is transferred into the reinforcing steel of the drilled shaft by bond and into the concrete by compression.

b. When the cap section is a steel element, appropriate design shall be developed to transmit all loads, conforming to the requirements of Chapter 15, Part 1 or 2.

24.3.5 Group Action of Drilled Shafts

Evaluation of group shaft capacity assumes the effects of negative soil friction (if any) are neg- ligible.

24.3.5.1 Cohesive Soil: Evaluation of group capacity of shafts in cohesive soil shall consider the presence and contact of a cap with the ground surface and the spacing between adjacent shafts.

If the cap is not in firm contact with the ground, or if the soil at the surface is loose or soft, the individual capacity of each shaft having a diameter B should be reduced to a reduction factor times Qt for an isolated shaft. This factor equals 0.67 for a center-to-center (CTC) spacing of 3B and 1.0 for a CTC spacing of 68. For intermediate spacings, the reduction factor may be determined by lin- ear interpolation. The group capacity may then be computed as the lesser of:

1 ) the sum of the modified individual capacities of each shaft in the group, or

2) the capacity of an equivalent pier defined in the perimeter area of the group.

For a shaft group with a cap in firm contact with the ground Q„„ may be computed as the lesser of:

1) the sum of the individual capacities of each shaft in the group or

2) the capacity of an equivalent pier as described above.

For the equivalent pier, the shear strength of soil shall not be reduced by any factor to deter- mine the Q, component of Q^,, the total base area of the equivalent pier shall be used to determine the Q, component of Q„|, and the additional capacity of the cap shall be ignored.

24.3.5.2 Cohesionless Soil: Evaluation of group capacity of shafts in cohesionless .soil .shall consider the spacing between adjacent shafts. Regardless of cap contract with the ground, the indi-

40 Bulletin 760 — American Railway Engineering Association

vidual capacity of each shaft should be reduced to a reduction factor times Qj for an isolated shaft. This factor equals 0.67 or a center-to-center (CTC) spacing of 3B and 1.0 for a CTC spacing of 88. For intermediate spacings, the reduction factor may be determined by linear interpolation. The group capacity may be computed as the lesser of:

1) the sum of the modified individual capacities of each shaft in the group, or

2) the capacity of an equivalent pier circumscribing the group, including resistance over the entire perimeter and base areas.

24.3.5.3 Group in Strong Soil Overlying Weaker Soil: If a group of shafts which is embedded in a strong soil deposit overlies a weaker deposit (cohesionless and cohesive soil), consideration shall be given to the potential for a punching failure of the tip into the weaker soil strata.

If the underlying soil unit is a weaker cohesive soil strata, careful consideration shall be given to the potential for large settlements in the weaker layer.

24.4 Material

24.4.1 Concrete

Unless otherwise stipulated in this specification, concrete shall be produced and place in accor- dance with Part 1 of this chapter. Concrete shall have a minimum compressive strength of 3,000 psi (21 megapascals) in 28 days. Approved additives, such as set retarders, may be used to improve workability. Slump at time of placement shall be not be less than 4 inches (100 mm), and not more than 6 inches ( 1 50 mm). If temporary casing is to be used, the slump should be not less than 5 inches (125 mm), and a set retarder may be necessary.

24.4.2 Reinforcing Steel

Unless otherwise stipulated in this specification, any required reinforcing steel shall conform to the requirements of Part 1 of this chapter.

24.4.3 Steel Casing Material

If the steel casing is relied upon as a structural element, the steel casing material shall conform to the requirements of ASTM A252.

24.5 Construction

24.5.1 Contractor Qualifications

Drilled shafts shall be installed by the Owner with experienced personnel, or by a Contractor or Subcontractor who specializes in such work. Availability of all required special equipment, tools, and experienced personnel are important items to be considered when determining Owner installa- tion or selecting an installation contractor.

24.5.2 Shaft Excavation

When excavating a drilled shaft, earth walls shall be adequately and securely protected against cave-in, subsidence and/or displacement of surrounding earth, and for the exclusion of ground water by means of temporary or permanent steel casings.

Whenever personnel are required to enter the shaft, a protective casing shall be used and there shall be adequate provisions for fresh air, light and protection from falling objects and toxic gases. Operation of harmful gas-producing equipment in the shaft must be prohibited.

Rock grapples or special tools for removal of boulders or other obstructions must be readily available for use. Blasting will be permitted only upon obtaining written approval from the Engineer.

Inspection of the shaft base, and any socket, by a qualified inspector is highly recommended and should be omitted only with the approval of the Engineer.

Proposed Manual Changes 4 1

No shaft excavation shall be made within 15 feet (4.5 meters) of an uncased shaft filled with concrete that is less than one day old. The construction procedure used shall be approved by the Engineer in charge before commencing work.

24.5.3 Casing

Where called for, permanent steel casing shall be installed to the plan elevation or to the eleva- tion designated by the Engineer in the field. When the top of the drilled shaft is below the surface of the ground, installation of additional large diameter casing may be required to extend above the work- ing level to minimize possibility of foreign materials or water entering the top of the shaft.

Casings shall be of adequate size and thickness to safely retain the adjacent earth materials and water form entering the shaft excavation, without exceeding allowable steel stresses, distortion, or collapse of the casing.

A protective casing is also to be provided, where required, to serve as protection for personnel entering the shaft excavations not provided with casings as specified above. Casing size and thickness shall meet the requirements stated above. The outside diameter of the protective casing shall be as large as possible, yet small enough to be lowered and removed without damage to the sides of the shaft.

If conditions are such that casing withdrawal will cause dislocation of the reinforcing steel or permit sloughing soils to enter the shaft, a double casing should be used. By this method, the shaft is drilled oversize and a temporary casing installed. A light gage permanent inner casing the same size as the required shaft diameter is then installed. This inner casing shall be of sufficient strength to serve as a form for the concrete shaft but need not be designed for soil pressure. Concrete is then placed within the permanent inner casing. After the concrete has set, the annular space between the permanent casing and surrounding soil is filled with grout, lean concrete, sand or by other approved method and the temporary outer casing is withdrawn.

24.5.4 Bells or Underreams

Before belling, the Engineer shall determine that the formation encountered at the plan eleva- tion is adequate. When shafts are required to be belled, the bells shall be formed either by hand or use of special belling equipment to the angle and slope called for on the drawings. The bottoms of bells shall be thoroughly cleaned of all loose materials and inspected before the concrete is placed.

24.5.5 Sockets

When sockets are required, they shall be formed by machine or by hand to the proper size and depth called for in the plans. Sides and bottom of sockets must be thoroughly cleaned of all loose material since the bond of the concrete to the socket sides is used in design.

24.5.6 Tolerances

The center of the top of each shaft shall not vary form its design location by more than '/:4 of the shaft diameter, or 3 inches (75 mm), whichever is less, and the shaft shall not be out of plumb by more than 1.5 percent of the length not exceeding 12.5 percent of shaft diameter, whichever is less.

24.5.7 Dewatering

Suitable dewatering procedures shall be as agreed upon between the Engineer and Contractor as determined at such time as conditions warrant. Unless otherwi.se agreed, the shaft at the time of placement of .steel reinforcing cage, if any, and concrete shall be essentially free of standing water in excess of two inches (50 mm) deep.

24.5.8 Inspection

Immediately prior to placement of any required reinforcement or concrete, each shaft shall be thoroughly inspected as directed by the Engineer to ascertain that the shaft has been properly pre- pared, that the bearing material is compatible with design requirements, and whether additional

42 Bulletin 760 — -American Railway Engineering Association

investigation of the bottom is required. If conditions vary from the assumed conditions determined by the borings, additional investigation shall be conducted as directed by the Engineer

24.5.9 Placing Steel

When reinforcing steel is specified, it shall be prefabricated and placed as a unit immediately prior to concrete operations. In order to minimize displacement of reinforcing steel cage when cas- ing is pulled, the cage may be reinforced below the zone of significant bending moment by welding horizontal bands to the cage at about five-foot (one and one-half meters) intervals.

24.5.10 Placing Concrete

Dry Hole — Prevent segregation of concrete through use of tube, sectionalized pipe or other means to direct the free fall of concrete so that it does not strike the sides of reinforcement in the shaft.

Under Water — Utilize a tremie or pumped concrete in accordance with Chapter 8, Part 1, Article 1.14.10 and Part 24, Article 24.3.2.7.

Rodding or mechanical vibrating is necessary only for the top five feet (one and one-half meters) of shaft. Any special requirements for concrete placement shall be approved by the Engineer.

24.5.11 Casing Removal

In situations where temporary casing is to be removed, the head of concrete inside the casing must be adequate to preclude infiltration of water and sluffage of the shaft face and sides.

Elapsed time from beginning of concrete placement in cased portion of shaft, until extraction of casing is begun, shall not exceed one hour.

Extreme care shall be taken when a casing is removed to prevent subsidence of the surround- ing ground if this condition is critical due to the presence of surrounding structures or utilities.

Elevation of top of the steel cage should be carefully checked before and after casing extrac- tion. The top of the concrete shall not raise during extraction of the casing.

The exterior temporary casing, if a double -cased shaft, shall not be removed until three (3) days after the shaft is poured.

24.5.12 Continuity of Work

Drilled shaft construction work shall be planned so that all required operations proceed in a continuous manner until the shaft is complete. A precise time schedule agreement between the Contractor and the Engineer should be established. Provision shall be made for protecting the shaft and adjacent construction in case of unforeseen interruptions. Such provisions shall be approved by the Engineer before drilling begins.

24.5.13 Records

An accurate record shall be kept of each drilled shaft as installed. The record shall show the top and bottom elevations, shaft and bell diameters, depths of test holes if required, date the shaft is exca- vated, inspection report of the bearing stratum, depth of water in excavation at time of placing steel and concrete, quantity of concrete placed compared with theoretical quantity, and any other pertinent data. Records shall be made and signed by both the project superintendent and inspector and distrib- uted to proper authorities daily.

24.6 Testing

Materials used in construction of drilled shafts should be sampled and tested as specified else- where in Chapter 8. At least two (2) concrete test cylinders shall be taken for each shaft.

Further testing of the shafts may be required by the Engineer in order to determine the quality of the concrete by coring of the bearing capacity of the shaft, by test loading.

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44

Proposed Manual Changes 45

Proposed 1997 Manual Revisions to Chapter 16 — Economics of Railway Engineering and Operations

Part 4 — Railway Operations

Page 16-4-1. Insert the following Revised Part 4. Railway Operation.

Table Of Contents Section Page

4. 1 Introduction

4.2 Car Distribution

4.3 Trains

4.4 Train Management

4.5 Communications

4.6 Defect Detection

4.7 Line Capacity

4.8 Terminals

4.1 Introduction

The basic railway operation is to provide a transportation service by moving goods and people from one place to another This transportation service should be done safely and efficiently.

Goods or products are hauled in freight cars. Some cars are specifically designed for particular commodities, such as tank cars for liquids, auto-rack cars for automobiles and trucks, and stack cars for containers.

Passenger cars are designed to carry people, and include such variations as coaches, sleeping cars, diners and lounge cars.

For efficiency, cars are assembled into freight or passenger trains so that coupled units of motive power can move many individual cars, as required to meet specific transportation needs.

For a general description of railway operations, see "The Railroad: What It Is and What It Does," by John H. Armstrong, .^rd Edition. 1990, Simmons-Boardman Books, Inc., Omaha, NE.

Also, federal regulations have operational and maintenance impacts on railways. See Title 49 Code of Federal Regulations, Transportation. Of special interest is Subchapter C- Hazardous Materials Regulations, Parts 200-266.

For information on motive power, see Part 3 — Power, of this Chapter 16 of the AREA Manual of Recommended Practices.

Accordingly, this Part 4 on Railway Operations, focu.ses upon car distribution, train manage- ment, communications, defect detection, line capacity, terminals and economic considerations.

4.2 Car Distribution

In order to provide good service to shippers, car distribution and control are key elements. Modem technology has contributed developments which improve the process of moving cars, both empty and loaded, to their destination on time.

A major technical development has been in the application of computers and communications in the field of car distribution. Mainly, this involves the use of computer work stations or PCs con- nected to main-frame computers with high-speed digital communications links.

Major railroads are handling car distribution from customer .service centers, where customers make toll-free calls to order empty cars or ask for reports on loads. In many instances, these are com-

46 Bulletin 760 — American Railway Engineering Association

puter-to-computer transactions between customers and railroads. Also, railroads and customers con- duct transactions over the Internet.

Car distribution is the process of moving empty cars to fill customers' orders. A major effort is to move empty cars the minimum distance to serve customers.

Empty cars generally show up at interchange points and in areas where traffic is terminated. Hence, accurate reporting of loads and empties is essential in planning for moving empties to fill shippers' orders in an efficient manner.

Some railroads schedule individual car movements. A car (whether empty or loaded) is only moved when its move is authorized by a movement order. Railroads that use this process typically have the customer service center handle this function, rather than local supervision.

Also, some railroads assign personnel to handle distribution of special cars or cars that handle specific freight, such as covered hopper cars, auto rack cars or double-stack cars.

4.2.1 Work Order Systems

Some railroads are implementing work order systems in which computer work stations (may be lap top computers) in locomotive cabs are linked to a railroad's customer service center. Digital train- to-wayside radio and microwave or fiber optic cable provide the communication path between way- side radio stations and the customer service center.

Customer service sends a work order to a train crew indicating cars to be picked up, set out, etc. The crews receive their orders on their on-board computer. They respond via the computer, record- ing their compliance. Thus, a written record is generated of orders and work accomplished. It is not unusual for an industry switch run to pull an empty car from one industry, reporting the pull, and receive an order to place the empty car at another industry for loading. Thus, real-time response enables the work order system to provide better customer service.

4.2.2 Automatic Equipment Identification

The most recent technological development to ensure good customer service is Automatic Equipment Identification. AEI provides accurate identification of freight cars and locomotives in space and time.

As of January 1, 1995, freight cars operating in interchange service were to be equipped with AEI tags identifying owner and car number. Locomotives were also equipped with AEI tags by Class I and regional railroads.

Railroads are installing wayside scanners to read AEI tags, especially bracketing major yards and at many interchange points.

The AEI wayside scanner provides location, date, time and train direction for all rolling stock, allowing trains to be tracked in real-time. Train consist information is stored at scanner sites until after the last car of the train has passed the scanner. Then, the tag readings are transmitted to a central office where AEI information is used to update the railroad's car reporting data base. This information is peri- odically sent to the Association of American Railroads' Washington, DC headquarters for updating the AAR's car data base and for informing shippers and other railroads of car movement information. The information is available to the railroad's car distribution and/or customer service center.

Loaded car locations can be reported to shippers and other railroads when interchange is involved. Empty car locations can be provided to customer service centers for car distribution planning.

Some railroads are installing AEI wayside scanners at hot bearing detector locations enabling car initial and number to be broadcast on detection of an overheated bearing.

Communications links are vital for sending AEI data in real time to a railroad's headquarters for input to the car reporting data base. Thus, timely information on car location can be automatically

Proposed Manual Changes 47

made available. This is especially helpful if AEI scanners are located on the departure side of yards to accurately report on cars leaving yards.

Additionally, AEI tags may contain variable information, such as temperatures of refrigerator cars or data indicating health conditions of locomotives. The AEI scanner can read such status of cars or locomotives and send the information to headquarters, which in turn can notify the train crew and yard forces of any problem. With variable information tag capability, equipment must be added to the normally passive tag to program it with this additional data.

Variable programmable message tags might also include information concerning hazardous material carried in a car.

4.2.2.1 AEI Economics

Costs associated with installing AEI tags and scanners (readers) include:

• Initial purchase price and in.stallation.

• Maintenance of scanners,

• Tag maintenance, if damaged. For variable message tags, cost of programming and periodic testing.

• Communications for storage and transmission of AEI data should include equipment and .soft- ware purcha,se and installation costs, as well as maintenance costs.

In the case of AEI, tags are usually a mechanical department responsibility. Scanners and com- munications equipment are typically a communications department responsibility.

4.3 Trains

Trains are a series of cars coupled together and hauled by locomotives.

4.3.1 Train Consist

Freight trains are usually made up for specific purposes depending upon the type of service to be provided.

For example, intermodal trains carrying trailers or containers are operated by a .schedule, and typically have enough motive power to move the train and meet the schedule by operating at track speed. On main lines, these trains usually operate in traffic control system territory where movement authority is governed by signal indications.

Regular freight trains may operate on a specific schedule or on a more general schedule, but one which allows trains to make connections. Often, over-the-road speed is not as critical for these trains as for intermodal trains. Under current operating agreements, these trains may make set offs and pick ups of blocks of cars at yards or at sidings on line.

Unit trains handle only one commodity, such as coal, grain, or produce, operating between a single origin point and a single destination point. Depending upon the commodity, they may operate as an intermodal train or on a more relaxed .schedule, as used in hauling coal. Cars for the.se unit trains are often unique and may be operated only in specific trains. Unit coal trains usually have the same cars operating both loaded and empty. Trains carrying automobile parts and completely assembled motor vehicles, although operated as a unit train, will not always have the same cars in each train.

Local trains operate on main lines, and also on branch lines. Sometimes they operate in one direction on one day, lay over at a terminal and return the next day. Some operate daily or on .selected days, making a complete round tnp over a portion of a line in one day. Industry runs are sometimes called locals, but they usually operate in a metropolitan or terminal area, returning each day to their originating terminal or yard.

4S Bulletin 760 — American Railway Engineering Association

Work trains are usually operated as extra trains, as required, to serve a specific purpose, such as distributing ballast, rail, tics, etc. Or they may be used to haul company material, as well as maintenance-of-way house trailers mounted on flat cars, between locations for gangs.

4.3.1.1 Passenger Trains

Passenger trains, especially for long distance rail operations, tend to operate in fixed consists of numbers and types of cars and locomotives. For long distance service, 20 cars is a typical maximum train length.

Factors to be considered in passenger train make up include:

• Adequate capacity to provide good service to meet customer requirements, e.g., a comfort- able seated ride.

• Motive power sufficient to provide on-time service to meet .schedules on a consi.stent basis.

• Train length short enough to require only one stop at station platforms.

Commuter rail service is substantially different from long distance service. Many of the oper- ating parameters are neariy opposite, if an efficient and effective service is desired.

A pattern of relatively short trains that serve a particular zone, providing fast service to the cen- tral business district, and then operate in fast non-revenue service back for a second revenue trip, pro- vides far more efficient and effective service than the traditional all stop local trains.

Commuter service requires a much higher level of on-time performance than either long dis- tance passenger or freight service. This on-time performance concept must be included in every aspect of design and operations. A 10 or 15 minute delay on a long distance train, although annoy- ing, will not cause the customer to use a competitive mode of transportation. A pattern of even minor delays will be sufficient reason for a commuter to return to his automobile. Commuter rail service requires exacting schedule development and precise operation.

4.3.2 Freight Train Length

There is no optimum train length, i.e., that will meet all requirements under all conditions. Generally, costs tend to favor long trains with minimum motive power. However, to provide good customer service, shorter, faster trains are often required. A railroad's goal is to achieve operational balance; to meet customer service requirements at minimum cost.

Train length is dictated by the length of passing sidings and by dynamic forces while handling trains in hilly territory.

Increasing train length to handle tonnage has both advantages and disadvantages. It is possible to estimate the costs and benefits of operating different lengths of trains, arriving at an optimum length of train for a particular movement. This cost/benefit analysis of train length is greatly aided by computer simulation techniques. Train movement simulation should take into account track, sidings, grades, curves and other physical operating characteristics, such as traffic density, tunnel locations, destination congestion, etc.

The primary objective of a railroad in private industry is to maximize profit. However, longer trains may work against the maximizing of profit, because they tend to reduce the quality of service and increase shippers' total distribution costs. The traditional bias toward longer trains may cause railroads to lower prices and reduce the quality of service. The result may be to reduce revenue through lower prices to retain a given amount of traffic, or moving less traffic at the same price.

4.3.2.1 Equipment Limitations

Car equipment can be a limitation to long mixed trains, particulariy with regard to buff forces and drawbar strength.

Proposed Manual Changes 49

Slack action occurs partly because of an undulating profile of the rail line. Changes in grade can be critical due to the impact forces set up between cars through the couplers, inducing a change of speed. This is most noticeable with long trains operating over a line having an undulating profile, even when the grades are not severe or limiting.

Air brake operation can be a limitation. It is usually necessary to limit the speed of long, heavy trains, because of greatly increa.sed stopping distances and inadequate signal spacing. In cold weather, it is often difficult to get the required air pressure gradient as called for by federal regulations. Recent developments (circa 1996) in electronic braking systems could solve these problems.

It is usual to limit the number of units of motive power on a train by specifying the number of powered axles that can be used. This is a function of the coupler .strength of the equipment.

There are .some elements to consider when several diesel-electric locomotive units are coupled together and controlled from the lead unit. Care in operation is required in limiting the number of units to prevent jacknifing of the train when braking. There is .some evidence that excessive dynamic brake applications on heavy trains may damage the track structure.

4.3.2.2 Remote Control Power

The development of control systems for the remote operation of locomotive units has made it possible to more effectively place power at other locations in a train consist in addition to the head end.

Remote locomotives are automatically actuated by a radio system in response to control input by the engineman in the lead locomotive unit. Effective train operation can be enhanced if remote control power is used to mitigate the difference in speed between relatively heavy tonnage bulk trains and high priority trains.

However, use of remote control power creates added difficulties in terminals, especially in auto- mated yards, to switch power out of the middle of trains, service the remote control units, and put them into other trains.

The following factors should be analyzed when considering remote control power utilization:

• Cutting in remote control power (slave units) at the originating yard is a co.st item as is the removal of slave units at the terminating yard.

• Using remote locomotives to increa.se train length may increase line capacity.

• Stopping distances decrease through the use of remote control power, as braking can be ini- tiated at more than ju.st from the head end of the train.

• Improved train performance and control from the intermediate spacing of power is especially important on heavy grades.

• Reduction of crew costs due to the reduction of the number of trains, as enginemen are not needed on remote control power (slave units).

• Control of slave units in mountainous territory, especially where there are numerous tunnels, may be discontinuous.

4.3.2.2 Operating and Plant Limitations Terminal Yards: Car inspection forces are staffed to handle normal trains within a reasonable period of time.

Charging trainlines is done in one of three ways: (1) by ground airlines; (2) by road engine crews; or (3) by yard engine crews. Where ground lines are available, charging time, and therefore cost is somewhat proportional to cut or train length. When the use of a road or yard engine is required, the cost of terminal time to the road crew must be considered, as well as lost switching service of the yard crew.

Terminal air tests are mandatory. Using ground air has numerous advantages, especially if used in conjunction with pre-testing. Ground air reduces crew costs and initial terminal delay, but it also reduces

50 Bulletin 760 — American Railway Engineering Association

locomotive and car detention costs. With pre-testing to better balance car inspector workloads, overtime and perhaps car inspector positions can be reduced as compared to charging with locomotives.

Doubling in or out of a terminal or a yard would appear to be a most important factor in deter- mining optimum train length. In determining the cost of such doubling, where not limited by high- way-rail grade crossings, consideration should be given to:

• Additional wage expense of the road crew if they perform this particular work.

• Delays to yard or terminal switching to and by other crews.

• The net income effect of these costs would then have to be weighed against the cost of elim- inating such doubling train movements.

Yard switching may be adversely affected by long trains blocking leads through the necessity of having to double into or out of receiving and departure tracks.

A train of twice the length of another train may require twice as much time to be pulled by a given point for inspection.

Fueling and Serx'icing Locomotives: Most railroads are putting an average of 1200 to 1 500 gal- lons into fuel tanks capable of holding more than twice that amount, because many other factors besides train length affect the need to fuel.

Locomotives are placed on service tracks for service, for minor repairs, for turning and consist building, as well as fueling. Once on the service track, the increased cost of fueling is almost nil. At a fueling rate of about 250 gallons per minute, the actual time to fuel is not as significant as the ben- efits of reducing the frequency of fueling.

Blocking: When a train picks up cars at an intermediate terminal, these cars must be arranged "out-of-block" as a unit to be dropped at a subsequent terminal for proper blocking for later train, or they may, at the cost of delay, be cut into the proper blocks in the first train.

On lines where weight restrictions exist over some bridges, a heavy car will have to be imme- diately preceded and followed by empty cars.

When possible, because of dynamic forces that occur on heavy grades, some types of cars such as long, light cars, should not be placed immediately behind the locomotive. Detailed treatment may be found in AAR Train-Track Dynamics reports. Also, loaded tri-level auto rack cars should not be placed next to open top loads such as sand, coal, sulfur, etc.

Hazardous material when hauled by rail are subject to federal regulations. Cars carrying haz- ardous materials shall be placarded to indicate the lading. Also, the position in the train of placarded cars is governed by federal regulations.

Over The Road: The effect of operating longer trains should be to operate fewer trains. Therefore, this will result in fewer train meets on line, providing it is physically and economically possible to extend the length of passing sidings. Some trains may be too long for passing sidings which could limit track capacity.

An effect of operating longer trains is usually to increase car cycle time.

Operating longer trains with minimum motive power units, so that they operate at lower speeds, could increase conflicts with trains operating at high speeds. The speed differential between the slower and the higher speed trains could become so great as to adversely affect scheduling and plan- ning for meets and passes. Motive power reliability must be at high levels.

The number and length of sidings fall into a group of semi-variable costs, which are those that occur only when the increase in density of traffic advances sufficiently to require additional sidings or lengthening or existing sidings. Simulation of train operations can be helpful in determining sid- ing lengths and spacing. AAR simulation models are available.

Proposed Manual Changes 5 1

The longer the train, the more likely it will affect both at-grade railroad crossings and highway- rail grade crossings, since each such crossing would be occupied by the train for a longer time period. Conversely, shorter trains result in more frequent service, which will impact both types of at-grade cross- ings, although the time required to traverse each crossing would be relatively brief. As for highway-rail grade crossings, the greater frequency of trains may result in higher exposure to accidents. Also, it should be noted that motorists become impatient waiting for long trains to clear the crossing. Where local governmental ordinances limit train speeds, repeal of such ordinances would permit train speeds to be raised which would reduce the time trains would occupy these highway-rail grade crossings.

Damage to equipment and lading results in large measure from the interchange of inertial effects caused by different parts of a train being on various gradients with portions stretched and oth- ers bunched and then balancing upon reaching level track.

Crew costs may be based on the number of diesel units operated, or total locomotive weight. Longer trains tend to increase extra crew pay incurred during terminal delays.

Comparative costs of operation and maintenance of ac versus dc traction motored diesel- electric locomotive should be considered. Some railroads are finding that, for a given horsepower, the greater adhesion of ac traction locomotives requires fewer locomotive units than dc traction loco- motive units. The brushless ac traction motor should reduce maintenance costs.

Helper Senice: An intermediate breaking up of trains to cut in helpers, or just adding helpers at the rear of trains to overcome heavy grades, is a time-consuming and costly process but is the most practical and efficient utilization of equipment.

The desirability of helper service depends on the nature of the route. If heavy grades are con- centrated, it is more economical to operate helpers on the heavy grades only than to run extra loco- motive units through the entire route, because they would not be needed on most of this territory. However, positioning helper locomotives and crews away from terminals, and the time spent cutting helpers in and out of trains, are significant costs. It should be noted that recent technology permits cutting off helper locomotive units on the fly without stopping the train.

Track Limitations: The operation of fewer long trains to move a given quantity of traffic increases the time available for track maintenance and improves the utilization of m/w forces and equipment during schedule work hours.

The dynamic forces involved with train operation are not thoroughly understood, and has been a continuing subject of investigation by individual railroads and the AAR. It is known that train length is one of the factors affecting these forces.

Customer service covers frequency and dependability of service to both consignee and con- signor. This element is compri.sed of two categories: (1) customers whose product has a high time value (for example, manufactured goods or perishables) for whom frequency is of first importance; and (2) those whose product has a lower time value (for example, raw materials) with frequency not as significant, though service consistency may be important. It should be kept in mind that length and frequency are inverse variables, which both enter into the economics of the railroad. The customer who is concerned about a high time-value product, will be interested only in frequency and not in train length per se, assuming that lengths are restricted to a maximum limit before undesirable effects such as damage to lading from excessive slack action occurs.

Limitations of plant and track layout at origin and/or destination can incur additional railway cost by requiring switching or excessive loading or unloading time.

Interchange connections with other railroads and trains may be less reliable creating a lower quality of service for other traffic.

The effect of operating longer and fewer trains will normally be to increase the number of cars required.

52 Bulletin 760 — American Railway Engineering Association

Individual axle loads may be limited by track conditions and the structural capacity of bridges. The capacity of bridges is usually the limiting factor for the total weight of a car or series of cars. Also, the maximum dimensions of individual loads may be limited by restrictive clearances.

One effect of the operation of long trains will be the concentration of motive power on these trains which affects the flow cycle of motive power, especially if long trains are operated on a spo- radic basis.

The operating costs of long trains compared to short trains must take into account the savings such as reduced number of crews as opposed to the increased cost of terminal delay, switching, over- the-road time, as well as the effect of equipment and plant investment in the long term.

4.4 Train Management

Train management involves moving trains by designated authorization issued by dispatchers who use computers, radio and train movement (signal) systems.

To meet customer logistics requirements, an increasing proportion of cars are moved in scheduled trains. Unit trains such as those hauling coal or grain, while not operating on a fixed schedule, are moved to meet customer time requirements. Extra trains, often with no specific schedule are also operated.

Amtrak and commuter railroad operators run passenger trains on fixed schedules.

4.4.1 Dispatching

Dispatchers use two methods of issuing orders to move trains: (1) verbal orders to train crews, who write the order on a special form; and (2) verbal order to train crews to proceed, but where the train movement is governed by signal indications, where installed.

Computers are used extensively to aid train dispatchers. In Direct Traffic Control (DTC) or Track Warrant Systems (TWS), the computer is used to generate train orders, and safety checks are built into the software that prevents dispatchers from issuing conflicting orders. Also, the computer stores a record of orders issued.

Computer simulation, an important advance in modem technology, allows railroads to adjust to optimize schedules, mofive power assignments and car supply to meet customer service requirements.

4.4.1.1 Movement by Orders

In non-signaled territory, trains can be moved by written orders issued by dispatchers directly to train crews.

The Standard Code of Operating Rules of the Association of American Railroads has been the basis for operating rules of individual railroads. Variations of the Standard Code may be adopted by individual railroads. Additionally, several railroads may agree to a set of operating rules that will apply to all of them.

Dispatchers issue movement orders to train crews via train-to-wayside voice radio. In general, a crew member writes the order on a special form and reads the order to the dispatcher, who confirms a correct order (dialog between the two will make corrections, if required) with the date, effective time and dispatcher identity.

Also known as the train order system, this method of moving trains in non-signaled territory may be called DTC or TWS. In either DTC or TWS, limits are set for a train's movement. The lim- its may be mile posts, block names or named locations.

Under DTC or TWS, train crews report periodically to the dispatcher. Some dispatchers have forms on which this train crew reporting information is recorded. If the dispatcher uses a computer, he will input the information into his computer. Similar activity occurs when trains are operated in automatic block signal territory.

Proposed Manual Changes 53

4.4.1.2 Movement by Signal Indication

Train orders are issued for movement in Automatic Bloctc Signal (ABS) territory for meets and passes. However, train operations are normally governed by signal indications.

Train movements are authorized by signal indications in Centralized Traffic Control (CTC) or Traffic Control System (TCS) territory. Under TCS operation, the dispatcher controls the switches and signals. Operation through interlockings is also governed by signal indications.

When a train is ready to leave a yard or teminal, the train crew notifies the dispatcher, who will clear a signal authorizing the train to move. From then on, movement authority is by signal indication.

In TCS or CTC territory, the movement of trains is automatically monitored and OS (on sta- tion) time reports are automatically recorded by the dispatch computer or a TCS control machine.

General practice is to record all voice transmissions of both dispatchers and train crews. Recordings are usually kept up to six months or one year.

4.4.1.3 Dispatcher Territories

Dispatchers are usually assigned a specific territory. Its size depends on traffic load, on-track work by maintenance-of-way forces, signal maintenance, and the number of local trains or industry runs. Usually, there is more work for a dispatcher on the first trick (8 am to 4 pm), Monday through Friday than on other tricks or shifts. For second and/or third trick, or on weekends, adjacent dis- patcher territories may be combined.

Most railroads have placed all dispatchers at a central office at or near the railroad's headquar- ters building. With such centralization, as much as 5,000 to 20,000 route miles of line can be dis- patched from one location.

A few railroads have regional dispatch offices, handling about 5,000 road miles of territory.

An individual dispatcher may control 200-400 road miles of territory. Where traffic is heavy with several local and through trains and extensive m/w activity, an individual dispatcher may have a smaller territory, possibly 100-200 road miles.

Central versus regional dispatching for large railroads is a matter of management preference and cost. Advantages of one centralized dispatch center includes having only one of each of the following:

• Building where dispatching is performed, and its physical and environmental security.

• Power supply with backup, air conditioning, water supply, etc.

• Communications and interface to management information systems.

• Interface to railroad management.

• Interface to emergency services and communications along line of road.

Centralized dispatching has some disadvantages, including the co.st of alternate means of power supply and communications, realizing they support the entire railroad dispatch function. The.se alter- nate power and communications are required at regional dispatch centers, but are not as critical. When all dispatching is at one location, a failure of the power supply or communications could dis- rupt railroad operations throughout the entire system. In any case, a good disaster recovery plan is essential, including back up control at different locations.

4.4.2 Train Movement Systems

Train movement systems include automatic block signaling, interiockings, traffic control sys- tems and train control systems. Automatic block signaling and interiockings are often part of traffic control systems. In fact, TCS can be viewed as ABS with successive interiockings.

ABS, when included in a TCS system, usually governs train movements between ends of con- trolled passing sidings. In multiple track territory, ABS is often installed to govern movements only

54 Bulletin 760 — American Railway Engineering Association

in one direction, with a second track utilized for movement in the opposite direction. In single track territory, ABS with a variation known as Absolute Permissive Block can provide for following and reverse moves, yet this systems prohibits conflicting moves between ends of passing sidings.

Interlockings are provided where tracks cross, as well as where crossovers permit trains to move from one track to another and/or at junctions with other lines. Such track layouts may be com- plex, especially in terminal areas. Switches and signals are controlled in such a manner that conflict- ing routes cannot be obtained. In some complex interlockings, several simultaneous parallel train movements can be made safely, effectively increasing plant capacity.

The trend is to convert from local control to remote controlling of interlockings, or to incorpo- rate interlocking control into existing TCS or CTC systems.

Under local control, interlocking operators receive requests for train moves from train crews, yardmasters or dispatchers.

Automatic intedockings are usually located where two railroads cross at grade and where traf- fic on at least one railroad is light. The first train to occupy an approach track circuit to the inter- locking receives a signal indication to proceed, while conflicting routes are halted until the first train clears the interiocking.

4.4.2.1 Traffic Control Systems (TCS)

Traffic control systems may also be known as centralized traffic control. TCS and CTC are operationally indentical. In each, train movements are governed by signal indications. Switches and signals are controlled by dispatchers. Train location, switch position and signal indications are dis- played on a model board at the dispatcher's office along with a track layout.

In newer computer aided systems, the dispatcher may operate a PC or a computer work station (usually more powerful and with greater storage capacity than a PC). The work station is connected to a main frame computer with large storage capacity and high-speed retrieval and reading capacity.

A large display, such as back-lighted projection screens which shows the entire railroad, may be provided. In such ca.ses, the dispatcher can usually bring up a section he wishes to control into his work station display unit.

Some railroads use the work station concept whereby a dispatcher may have as many as three monitors to show his territory, but can bring up a small section to perform specific control functions. With this concept, the large display of the entire railroad is not provided.

4.4.2.2 Automatic Train Control Systems (ATC)

Automatic train control provides an additional safety system ovedaid on ABS orTCS/CTC ter- ritories to enforce speed restrictions. Although often classified as train control, cab signal systems do not enforce speed restrictions, but only bring signal aspects into the locomotive cab where they can be seen by the train crew. This is especially helpful in fog or with heavy snowfall conditions. Also, cab signals continuously reflect the track conditions ahead of the train. If a switch is open, for exam- ple, it is immediately shown by a cab signal downgrade. The engineman need not wait until he sees a wayside signal to take action. Conversely, if a train ahead should clear the main track, the follow- ing train's cab signal will upgrade to a more favorable aspect, allowing the engineman to increase speed. There is no need to continue at a slower speed until a wayside signal can be seen.

Brake control can be incorporated into the cab signal system to initiate braking, should the engineman fail to acknowledge a change to a more restrictive cab signal aspect.

Other train control systems include intermittent inductive train stop, and continuous speed control.

The intermittent inductive system uses wayside inductors or beacons located just in approach to wayside signals. Upon a more restrictive wayside signal, an audible indication sounds in the loco- motive cab, alerting the engineman that the wayside signal is displaying an aspect to move at a more

Proposed Manual Changes 55

restrictive speed. The engineman must acknowledge within 4 to 6 seconds or a penalty brake appli- cation is automatically applied, which brings the train to a complete stop.

With continuous speed control, the speed of the train is monitored in addition to track condi- tions. When conditions call for a lower speed (train ahead, for example), an audible indication is .sounded. If the engineman responds within 4 to 6 seconds by operating an acknowledgment lever and brings the train speed down, he maintains control of the train. If he does not acknowledge, or if he acknowledges but does not reduce train speed, a penalty brake application is automatically applied that brings the train to a complete stop.

Generally, if continuous speed control is placed in service, the locomotives are also equipped with cab signals.

On rail transit lines and on a few commuter rail lines, an intermittent train stop system is installed with a trip stop arm at each wayside signal location. When the wayside signal indicates Stop (a Red aspect), the trip is in the up or raised position. If the train pa.s.ses this Stop signal, the trip arm is struck by a car or locomotive mounted brake paddle releasing the air from the brake system and the train is brought to a complete stop.

4.4.3 Economics of Train Management

Costs associated with improved train management systems depend upon a number of variables. These should be considered and may not apply in all cases. Some are added costs, others will pro- vide savings.

The variables to be considered when making a complete economic study of proposed train man- agement systems include:

Payroll: For train crews, road hours may be reduced by improved over-the-road time, and ter- minal time may be reduced by the ability to dispatch trains more quickly and efficiently.

For dispatchers, payroll costs should be reduced by centralized dispatching or consolidation of territories resulting in fewer dispatchers required.

For interlocking operators, payroll costs can be reduced by remotely controlling plants or bring- ing interlocking control into TCS or CTC territory. Either of these control changes reduces the num- ber of interlocking operators required.

Signal maintenance forces increase as train movement systems are expanded. Communications maintenance forces increase as more radio and data communications facilities are upgraded and expanded. This is especially true where defect detectors are equipped with "talkers" or radios to report conditions directly to train crews.

Train Time: Improved performance should reduce origin-to-destination running time.

Train hours are decrea.sed through shorter standing time for meets and passes, fewer train stops and reduced elapsed time when trains move through power and spring switches. With long passing sidings in TCS or CTC territory, non-stop meets may be accomplished.

A reduction in train running time improves the ratio of train miles per train hour.

Train miles may be reduced due to increased tonnage of trains through improved performance. Average train speeds should increase.

Crew wages may be adjusted for the decreased train time, but savings depend upon labor agree- ment provisions.

There may be reduced locomotive requirements through reduced train miles and reduced loco- motive time.

36 Bulletin 760 — American Railway Engineering Association

Train Stops: The costs of stopping trains, especially for meets and passes is reduced with improved TCS or CTC. With long sidings or sections of double track and single track, non-stop meets and passes can occur.

Fuel savings would result from fewer stops and often less waiting time in sidings in traffic con- trol territory.

Brake shoe wear is reduced through elimination of stops and slowdowns.

Some small cost reductions may be achieved through less frequent replacements of rails and wheels, due to reduced wear as a result of fewer train stops and slowdowns.

Freight train delay time is reduced. With fewer stops and less delay, damage to lading is reduced providing better service to shippers.

Taxes are affected by changes in plant and can be significant if double track can be replaced with single track TCS or CTC with passing sidings.

Overall maintenance costs with new train movement systems include both increased and decreased expenses. For example, if a second main track is removed, there are less track maintenance costs. But with more signal equipment required, there are increased signal maintenance costs. Also, with second track removed, rate of track geometry changes and track component degradation can increase (more trains over remaining track).

If dispatcher consolidations can be implemented, associated costs are reduced.

The improvement in motive power utilization may decrease this maintenance cost.

Car Time: The same amount of traffic is moved at less expense with fewer car hours, due to improved over-the-road time. This postpones the necessity of increasing car inventory and reduces per diem payments.

Depreciation changes due to the increased or decreased plant.

Safety can be expected to improve due to increased mileage of train movement systems. There should also be a decrease in the number and severity of accidents.

Investment changes result from the reduction of double track by the installation of the TCS or CTC. Also, if these traffic control systems are applied to single track, they increase its capacity and defer the requirement to install a second track.

For planning expenditures, first consider whether changes in plant or operations can be made without the installation of new train movement systems.

Intangible benefits also should be considered, including better customer service, increased flex- ibility in operations and improved productivity.

Weather conditions affect operations, and costs are associated with weather. For example, one should consider snow removal as a cost, as well as costs to recover from floods or other weather related occurrences.

4.5 Communications

It should be noted that communications facilities and services can be provided by the railroad or transportation agency.

Also, it is possible that all or part of communications facilities and services can be provided by other entities, such as communications common carriers and other private communications companies.

Costs for installation, operation and maintenance have to be analyzed including the condition of owning the communications facilities, leasing them, or having the entire communications plant and service provided by an outside entity.

Proposed Manual Changes 57

One factor to be considered in providing communications by the transportation carrier is that of control and recovery after natural disasters.

4.5.1 Essential Communications

Digital and voice radio can connect wayside stations to moving trains. For dispatcher-to-train crew communications, this can be a voice link and/or a digital voice system. A digital data link is needed to transmit data between control centers and the train. The link from the moving train to the wayside is via radio; but the link from the wayside radio station to the control center can be fiber optic cables, microwave radio systems, UHF or VHF radio station segments, or leased communica- tions circuits. The fiber optic cable provides high capacity with room for expansion and is immune to electro-magnetic fields created by electrified rail lines or electric power transmission lines.

Inductive communications technology is often used to transmit data from track to train via bea- cons, "'wiggly wires", inductors or transponders. Coded track circuits in the rail can transmit signal- ing data, speed commands, etc., to a train. Other systems that do not use coded track circuits can u.se digital radio links from the wayside to a train equipped with an on-board computer to handle the con- trol and information function.

4.5.2 On-Board Communications

On board the train, voice radio may be advisable with portable handsets for crew member com- munications. For passenger trains, a suitable location mid-train, such as a dining or lounge car, could be a conductor's station equipped with 30 to 50 watt output radio enabling him to contact the control center or dispatcher.

4.5.3 Emergency Communications

During an emergency when the train is not operating under normal conditions, communication is of extreme importance. Battery-powered handheld radio sets are most useful, but standby power sources or batteries should be provided for the 30 to 50 watt radio tran.sceivers to enable train crew members to contract a control center and local emergency services. The radio communications load should be considered when sizing battery power for radio equipment.

4.5.4 New Technologies

Cellular and satellite radio communications offer additional wireless links between moving trains, m/w forces and railroads' regional offices. Also, some railroads are investigating the use of Global Positioning Satellites (GPS) for determining train location, and physical plant mapping. Also, being looked into is the use of satellite communications for high volume communications to link rail- road headquarters with regional and off-line offices. Satellite communications could reduce the requirements for land lines, microwave or cable links. Again, this requires an economic study of costs of the various forms of communications covering installation, operations and maintenance.

4.6 Defect Detection

See Part 5, Economics and Location of Defect Detector Sy.stems, in Chapter 16 of this Manual.

4.7 Line Capacity

The basic operating capacity of a segment of railroad track to handle train movements is depen- dent upon the speed of trains and the distance between them. The speed of a train over a specific seg- ment of railroad is. in turn, dependent upon the ratio of horsepower to gross tonnage of the train and the grades, curves and other such features encountered by the train. In single track, double direction operation, the distance between trains is a function of the distance between usable sidings. A usable siding is one that must be clear for an opposmg tram to enter and pass through in a normal, straight- forward movement, and also long enough for all trains to clear the main track before stopping. The

58 Bulletin 760 — American Railway Engineering Association

distance between trains is dependent upon the length and number of signal blocks used to space trains within double track territory under smgle direction operation. Signal spacing is a function of the stop- ping distance of a maximum tonnage train operating at the maximum authonzed speed; this will pro- vide the maximum stopping distance for all trains in this territory.

Line capacity can be expressed by the formula:

C, = C,xE

where

C|, = Practical line segment capacity

C, = Theoretical line segment capacity

E = Dispatching efficiency for line .segment

The dispatching efficiency of a railroad varies by territory and can be influenced by many fac- tors. Some of these are relatively predictable while others are completely random.

The type of signal system is a major influence on the dispatching efficiency. Traffic control sys- tems have a much higher efficiency than dispatching in non-signaled or "dark" territory. Automatic block signaling falls somewhere between these two mentioned above.

Radio communications for train-to-wayside functions can increase dispatching efficiency, as well as radio "talkers" at defect detector installations.

The type of traffic moving over a segment of a railroad influences the line capacity and the dis- patching efficiency. A bridge line has a much higher dispatching efficiency than a line with many industries and yard limits. The movement of yard engines and local freights can reduce the line capacity for through movements.

The physical characteristics of a line also influence dispatching efficiency and line capacity. A line with heavy grades or undulating territory, which may have a higher incidence of train separa- tions, has a lower dispatching efficiency than a line with fewer hills and resulting abnormalities in train operation.

Also impacting line capacity are maintenance operations, such as allowing time and track for maintenance-of-way work. Some railroads provide "windows" for m/w work and later fleet trains after the work is completed. MAV work is a fact of life and should be taken into account when cal- culating line capacity. It should be pointed out that on many railroads, such as those in northern cli- mates, m/w work is usually done in spring and summer weather. Thus line capacity is impacted dur- ing certain times of the year. Of course, one can make the point, that snow clearing also affects line capacity. Thus weather and m/w work should be taken into consideration in any line capacity study.

All of the factors mentioned so far are relatively predictable for a given line segment. Other fac- tors which are completely random in their effect include locomotive failures, derailments, overheated bearings ("heatboxes"), highway-rail grade crossing accidents, temporary slow orders, etc. Any occurrence which prevents a train from making its scheduled running time tends to lower the dis- patching efficiency of a line.

Some factors such as locomotive failures, hotboxes, and highway-rail grade crossing accidents may be random in the short term, but can be managed over the longer term.

Since these factors are random, their statistical prediction may be possible if conditions are sim- ilar for a large number of trains.

The theoretical capacity of the line segments is determined by the formula:

_ Time x N ^1 ~ TT

Proposed Manual Changes 59

where

Time = number of units of time in the period for which capacity is being calculated, for exam- ple, 1440 minutes in a day

N = the number of directions run on a single track (either 1 or 2)

H„ = the maximum gross headway in N directions

For double-track, single-direction running (N = 1), gross headway (H,) is the average minimum time between trains in a minute.

This can be calculated using the formula: „ Db X Bn

Hi —

' V

where

V = average speed of trains over a line segment

Db - average signal blocks length

Bn = number of signal blocks separating trains operating on a proceed signal indication

For single-track, two-direction operation (N - 2), the gross headway (H,) is defined by the formula:

H, = R, -I- R, -t- T, -t- T,

where

R, = minimum unopposed running time in direction 1 for the train with the lowest horse- power to gross tonnage ratio on the line segment in direction

T| = the time necessary for a train in one direction to enter a siding, clear the main track, return the turnout to the normal position such that the opposing train may proceed.

In single-track, two-direction territory, gross headway is the minimum period of time one train could operate following a previous train from siding A to the next siding B, if the opposing train at siding B is to be moved from B to A between the trains. In using the formula, care must be taken to ensure that all values used are in like units. Generally, distance is expressed in feet, time in minutes, and speed in feet per minute.

After calculating the capacity of a line segment, its load factor is calculated. This is done by dividing the number of trains currently being operated over the line segment by the practical capac- ity of the line segment, and multiplying by 100 to find the percentage.

The practical maximum line capacity is about 75% of the potential capacity given by these for- mulae. The contributing factors include: (1) automatic block signals, (2) quality of dispatcher-to-train radio coverage. (3) extent of local business, and (4) track profile characteristics or incidences of train separation.

Operation of a line at too high a load factor is not a desirable characteristic, because little capac- ity remains for unplanned movements such as extras or detours. The availability of track time for maintenance work becomes limited as the load factor increases.

To determine the bottleneck segment of a line, the highest load factor is of more importance than the lowest capacity segment. Any plans for plant improvements to expedite train movements must fall into one of two categories. The speed of trains must be mcrea.sed or the distance between trains must be decreased. Line or route modifications or changes in the horsepower to gross tonnage ratio will affect the speed of the train. Changes in the location of siding and/or changes to the signal system will affect the spacing of trains. Efforts in these areas yield optimum economic benefits when directed to those segments with the highest load factors.

60

Bulletin 760 — American Railway Engineering Association

In practice, many railroads employ sophisticated computer simulation models that "run" vari- ous segments of the railroad at different loading levels based on actual or projected schedules, to pin- point bottlenecks to improve train flow.

The absolute value of the load factor or comparison to some standard is not really all that impor- tant. The importance of the load factor is in enhancing management's capability to rank portions of the railroad so as to be able to direct capital improvements where they will have the greatest benefit. For this reason, the selection of an exact dispatching efficiency is not all that critical. Theoretical line capacity may be used just as easily. One must understand that capital funds are a scarce resource. Management requires a quantitative method of ranking demands. Return on investment is of prime importance, but in areas such as increases in railroad line capacity, calculation of return on invest- ment is rather imprecise. Ranking of line segments by "load factor" becomes even more important.

The preceding discussion has dealt exclusively with the "physical" capacity of a railroad line segment. Additional constraints may limit railroad operation to less than its physical capacity. One such constraint is the Hours of Service Law, which limits the on-duty time of train and engine crews. As the over-the-road time of trains between crew change points approaches the limit set by this law, the railroad is said to be "saturated", although the physical capacity of the line may not have been reached. In addition to the over-the-road running times and delay to meets and passes with other trains, other factors such as initial and final terminal delay, set-outs and pick-ups on line-of-road, etc., may affect the total crew on-duty time, and constrain the operating capacity of the railroad, as opposed to its physical capacity.

4.8 Terminals

Terminals are facilities dedicated to the performance of one or more specific tasks. These tasks may include car classification, car unloading and loading, and interface between various transporta- tion modes. Each type of terminal requires specific types of design and equipment to economically achieve its purpose. Terminals are covered in Chapter 14 of this Manual.

Experience has proved you can depend on them. WESTERN-CULLEN-HAYES

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Crossing Signals Gate Mechanisms Case & Track Hardware

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Telephone Shelter Boxes Lightning Arresters

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2700 West 36th Place • Chicago, Illinois 60632 Telephone: 773/254-9600 Web site: www.wch.com

Take advantage of Western-Cullen-Hayes service proven equipment and experi- enced railway supply personnel to assure safe, efficient operation on your line or in your yards. Call 773/254-9600.

Chemelron^s ATV.

Coming at you with more welding power than ever.

On track. Off track. Chemetron's latest technology All Track Vehicle (ATV) can deliver field welding sen/ices fast, and with more consistent flash-butt quality than any other in-track welder Ever.

The technology behind the weld quality of Chemetron's ATV is an improved K-900 welding head and the proprietary software our on-board computer uses to control welding cycles. Precisely.

Chemetron's mobile welder was engineered to exceed AREA specs, including

the "upset to refusal" requirements. Our computer system guarantees plant quality in-track welds. Continuously.

Offering optimum production for all rail sizes and metallurgies, Chemetron has complete mobile welding units for sale or lease, for short or long term contract welding. W\\h full engineering and maintenance "^^^*T^j support.

Put Chemetron's ATV in-track welder to work for you by calling Larry Taylor at 847-520-5454. Today.

61

Will the next rail you buy be fully heat-treated, head-hardened, or inter- mediate strength?

Will the next turnouts you buy be state-of-the- art manganese castings, vacuum -molded and machined for perfect fit?

The answer is yes, if you're out for the best rail products the world has to offer. And that means Foster-Class, from L.B. Foster Company. World-class.

Well go aCTOSS the coun- try or around the world to meet today's standards.

So you get a double advantage: world- class technology along with superior Foster fin- ishing and Foster servic- ing right here at home.

For instance, Foster supplied turnouts meet all AREA specs, and every inch is pre -inspected before shipment.

We go to special lengths on relay rail, too. Just as we've been doing for 80 years, we bring you the largest stocks in the world. And more. Today we take up and deliver pre -welded lengths up to a quarter- of

a-miletocutyour on-site fabrication costs. Go Foster-Class

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smallest orders.

Give us a call and we'll ship any rail order — including turnouts and accessories — on time, anywhere, from stocking points coast to coast. Plus special sections and long lengths of new rail, rolled to order

We're also your number one source for sophisticated track and contact rail components for transit systems.

The Foster difference is a world of difference. Because Foster- Class is world-class. Phone or write L.B. Foster Com- pany, 415 Holiday Drive, Pittsburgh, PA 15220. (412) 928-3400.

FOSTER

L.B.FOSTER COMPANY

62

Proposed Manual Changes

63

Proposed 1997 Manual Revisions to Chapter 18 — Light Density and Short Line Railways

Part 1— Track Components and Track Design

Page 18-ii. Add the following new Table of Contents. List of Tables and Table 1.1, Dimension and Surface Specifications for Relay (Second hand) Rail.

Table of Contents

Section/Article Description Page

1.1 Rail

List of Tables

Table Description Page

1-1 Dimension and Surface Specifications for Relay (Secondhand) Rail

Rail Sections - In Use Since About 1900 (See Plan 1001 in Portfolio of Trackwork Plans)

Table 1.1 Dimension and Surface Specifications for Secondhand (Relay) Rail

Length	Standard 39 ft lengths. Not more than \Q9c of lot between 33 ft and 39 ft. No rail shorter than 33 ft.
Vertical Wear	Average top wear '/» in. or less with maximum at any one loca- tion of Vi: in. (For yard and sidings, average top wear up to 'a in. with Vi.. in. maximum at a single location).
Side Wear	Maximum of 'A in. ('/^ in. for yard and sidings), with wear on one side only.
Lip or Overflow	Maximum of '/k, in.
Engine Bums	Maximum of '/; in. diameter (or 'A in. wide by Vi in. long) and Vn in. deep. Maximum of six engine bums per rail. Engine burns on no more than 8% of the lot.
End Batter and Chipping	Maximum of '/k. in. ('/» in. for yards and sidings) when measured '/: in. from the rail end with an 18 in. straightedge.
Running Surface Damage	Maximum of 'A in. wide by '/: in. long and '/'; in. deep. Flat spots are not permitted on the rail head.
Defects Not Permitted	Bolt hole cracks or breaks, broken base, crushed head, detail or engine bum fractures, head-web separation, piping, horizontal or vertical split head, torch cuts or fiame gouges, compound or transverse fissures, pitting.
Condition and Appearances Internal Inspection	Rail must be: free from obvious defects; clean in appearance; straight in line and surface and without kinks; and free from ba.se defects such as plate wear, spike notches, pitting, and fiame-gouging. Rail to be ultrasonically inspected before of after installation. Defective sections to be rejected and replaced.

r

MAGNUM

CONCRETE GRADE CROSSING

• Manufactured to fit any rail ranging from 115 lb to 136 1b.

• Designed for wood and concrete ties.

• Low maintenance — long wear.

• Custom designed for switches.

• Insulated crossings available.

MAGNUM MANUFACTURING CORPORATION (801) 785-9700 • FAX (801) 785-9701

Manufacturing locations in:

Pleasant Grove, Utah and Everman, Texas

MAGNUM

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Nolan Rail Products

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Push Cars

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64

Proposed Manual Changes 65

Revisions to the AAR Scale Handbook Part 5 — Vehicle Scales

Page 3-2. Committee 34 has reviewed Part 5, Vehicle Scales, and approved the following revisions, effective January 1, 1997.

5. 1 (c) Vehicle scales may be mechanical, analog, digital, or a combination thereof.

5.1 (d) All vehicle scales shall meet the specifications and requirements of the National Institute of Standards and Technology (NIST), Handbook 44, and State laws for the jurisdiction in which the scale is located.

(Editorial Note: Remove "comma" after the word 'specifications' in the Manual.)

5. 1 (e) Vehicle scales shall have valid NTEP Certificates of Conformance.

5.2.1 (a) The minimum pit depth, measured from the bottom of the weighbridge structure to the floor of the pit, should be:

5.2.3 (a) Lever stands of load cell base plates shall be properly leveled, and grouted if neces- sary, to provide even distribution of the load over the full surface of the stands or plates.

5.2.3 (b) Load cell base plates shall be leveled to a tolerance of not more than 0.015 in. per ft., with consideration to leveling the weighbridge transversely and on grade longitudinally.

5.2.4 (a) Piers must support the combined loads applied by the weight of the scale, the weigh- bridge, plus the maximum anticipated load on the scale, so that any settlement shall be uniform throughout the structure.

5.2.5 (a) A minimum of four (4) anchor bolts shall be used for load cell base plates where the design creates an uplift or shear reaction to the anchor bolts.

5.3.1 (a) Main girders for weighbridges shall not deflect more than 1/600 of the span at mid- point when loaded to the rated concentrated load capacity (Dual Axle Capacity).

5.6 All scales manufactured after January 1 , 1986, must be marked with the accuracy class des- ignation, nominal capacity, concentrated load capacity, scale division "d", and verification scale divi- sion "e" if different than "d", clearly on the device. Unless temperature range is 14 degrees to 104 degrees F (-10 degrees to 40 degrees C), the temperature range must be conspicuously marked.

5.12 The power requirements of the electronic instrumentation and load cell circuitry for elec- tronic scales must conform to applicable regulatory requirements and codes; and the scale must sat- isfy the tolerance requirement when scale equipment is subjected to RFl and EMI infiuences which may exist during normal scale operation.

Change 50 ties an hour under heavy traffic

Twenty trains per day use this track. Yet despite this heavy traffic, a single MRT-2 Tie Changer can replace 50 ties an hour in an average day. The secret is the quick on-off track- ability designed into the MRT-2. In less than two minutes, any place along the line, it can climb on or off track com- pletely under its own power. Old ties - even switch ties - are rerrioved whole, with minimal disturbance to track structure.

If you're now wasting valuable time clearing for trains, switch to the MRT-2. Sales and service available throughout North America. Contact us for a free demonstration.

m^SMi

MODERN TRACK MACHINERY INC.

1415 Davis Rd., Elgin, IL 60123-1375

Tel. (847) 697-751 0 Fax: (847) 697-01 36

MODERN TRACK MACHINERY CANADA LTD.

5926 Shawson Drive, Mississauga, Ontario L4W 3W5

Tel. (905) 564-121 1 Fax: (905) 564-1217

66

NORFOLK SOUTHERN TRACKSIDE LUBRICATION STUDIES

1997 Interim Report

By: D. E. Cregger*

Abstract

Interim results from detailed monitoring of rail wear related to trackside lubrication equipment and lubricant has revealed significant differences in equipment and lubricant performance. The effect of rail profile grinding on high rail gauge face wear was defined for 9-degree, 6-degree, and 4-degree test curves. Significant opportunity was found for increasing rail metal wear life and increasing the efficiency of lubrication.

Good afternoon. I am plea.sed and honored to present to you today the interim findings of the Norfolk Southern trackside lubncation studies. These on-going studies were initiated due to a loss of shunt incident in 1992. The results of our first tests were shared at the 1994 As.sociation of American Railroads (AAR) sponsored Town Hall meeting in Kansas City. Those findings of large percentages of grease waste were later corroborated through independent testing by the Association of American Railroads-Technical Test Center at Pueblo, Colorado. We learned a great deal with our first tests and were compelled by the potential benefits to continue the studies.

Time constraints prevent the presentation of all the procedures, techniques and the many vari- ables encountered during the studies of equipment, grease and rail wear. However, it is important to understand that much equipment and grease improvement was required before rail lubrication bene- fits could be monitored through rail metal loss. Also, note that the test site length grew as we suc- cessfully extended grease carry for proper lubrication. Grease carry that deposits on the rail head instead of the gauge face and comer does not provide metal wear protection and, therefore, was not a factor in determining carry distance. The selected test site is an example of grease deposited on the rail in a non-productive manner

The test site (Exhibit 1) is a single track of 1993 vintage Nippon 136RE premium rail with 65 MGT traffic that is 95% one direction (eastbound loaded coal trains, mixed freight and grain trains). Train movement is from MP-V298.5 through MP-V295.5 with an ascending grade of 0.10%. Locations to monitor curvature high rail wear were established at (orange marks):

Milepost Rail Curvature Description

V298.5 Tangent Lubricator

V298.3 North 9.3-deg R Lst curve after lubricator, 0.2 miles

V297.8 South 6.0-deg L Lst curve after lubricator, 0.7 miles

V296.0 North 4.0-deg R Last curve in test site, 2.5 miles

A lubricator installed at V297. 1 was removed from service so that baseline wear rates for unlu- bricated rail could be established at V296.0. When we started, grease was being carried intermittently from the lubricator into the curve bodies of the:

1 . 9-degree curve for 0.3 miles on the high rail (aprox. 0.3 miles including tangent on north rail).

2. A similar distance on the high rail of the 6-degree curve (total carry of 0.7 miles including tangent and low rail of the 9-degree curve).

♦A.ss'i. Manager — Chemical Technology, NS.

67

68

Bulletin 760 — American Railway Engineering Association

in
O)
CM
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in	<o
CO	■♦-'
O)	(/)
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to CO	o
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O
St
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	*i		*i		c.
1-	(0		(0		(U lii
Q.	0)	2	(D	o 8
O	3	8	3	" i«
0)	o	'k.	O		Last test;
HI Q		_2	2	^ ^
LU
t£.
3	q:		^		or
1-	O)		O)		C3)
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LU	00		h-^		(b
_l	o^		05		o>
	CM		CNJ		CM
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Exhibit 1

Trackside Lubrication Study

Whitethorne District Milepost V295.7 to V298.5

Paper b\ D. E. Cregger

W

Improvements to equipment and grease resulted in consistent liihrication /protection 3.0 miles from the lubricator. This surprised us. but even more amazing is that the grease consumption was reduced by 30'7c.

A tribometer was used to a limited extent to confirm presence of lubrication. We quickly found that the presence of a low co-eftlcient of friction reading did not indicate that the gauge face was pro- tected from wear. Every wheel was not being lubricated while passing the trackside lubricator. Dry wheels were found to be wiping away lubrication and wearing away gauge face metal (Exhibit 2).

Once this mechanism was recognized, we realized that the rail is the working grease reservoir. Grease maintained on the gauge face must be adequate to furnish rail gauge face lubrication and sup- ply sufficient grease volume for transfer to dry wheel flanges. The volume of grease required on the rail gauge face is dependent on the efficiency of the wiping bars and the pumping system.

The effectiveness of this lubrication method was determined by using a Starrett dial indicator and a measuring frame manufactured by Track Renewal Engineering. Inc. to measure rail wear (Exhibit 3). The following analysis focuses on the high rail gauge face wear of the three points mon- itored for rail wear.

Rail dimension measurements were collected 42 times in a 678 day interval (Exhibit 4). The AAR wear rates (noted at the bottom of the table) for differing lubrication conditions developed by Elkins et al-1984 were used as guidelines to describe lubrication conditions as related to gauge face rail wear. The semi-dry wear rate (wear in the presence of grease deposited somewhere on the rail head and face) was determined for each inspection point. Note that the semi-dry wear rate will vary w ith the operational and location conditions of each railroad.

P **

^^^^i^war

Exhibit 2 Grease Consumed by Dry Wheels

70

Bulletin 760 — American Railway Enjiineerini; Association

Exhibit 3 Track Renewal Engineering, Inc. Rail Gage

TABLE 1; COMPARISON OF CURVES AND SITE WEAR RATES (Basis is Semi-Dry Rail)

CURVE, LOCATION, CONDITION	9.3R V298.3, .IN 100-MGT	9.3R %	6.0L V297.8, IN 100-MGT	6.0L %	4.0R V296.0, IN 100-MGT	4.0R %	SITE AVG, IN 100-MGT	SITE AVG %
LUBRICATED RAIL	0.0284	14	0.0057	3	0.0200	6	0.0180	7
PROFILE GROUND	0.0348	17	0.0207	10	0.0396	11	0.0317	13
SUMMATION	0.0632	31	0.0264	13	0.0596	17	0.0497	20
REDUCTION	0.1390	69	0.1861	87	0.2888	83	0.2047	80
SEMI-DRY	0.2022	100	0.2125	100	0.3484	100	0.2544	100

AAR WEAR RATE DEFINITIONS: (INCHES PER 100 MGT)

Dry Rail 0.5000 Low Lubrication O.IOOO

Medium Lubrication 0.0290 High Lubrication 0.0064

Exhibit 4

Paper by D. E. Cregger 7 1

Therefore, for this presentation the wear rate will be referenced as NS Semi-Dry. As we improved lubrication performance, wear rates for lubricated wear and the effect of rail profile grind- ing on gauge face wear was measured. The difference between semi-dry and the combination of lubricated and profile grind wear is the potential improvement. It is interesting to note that we dupli- cated AAR High Lube conditions at the 6-degree curve (6L-V297.8) test location.

Graphically displayed (Exhibit 5), the four tallest bars (NS Semi-Dry Rail) represent the gauge face wear of the rail after equipment improvements made consistent operation possible. With further improvements in equipment and grease formulations, lubricated gauge face wear in all the test loca- tions, the first bar shown for each location, was reduced to at least AAR Medium Lube. Analysis of data collected allowed us to define the gauge face wear effect of rail profile grinding, the second bar shown at each location.

The benefit of gauge face lubrication was negated for 30-60 days after rail profile grinding. Gauge comer relief removed the rail geometry necessary for grease transfer to the rail face. The grease migrated along the wheel profile and deposited at the gauge side of the rail crown. Gauge face lubrication was renewed when rail wear created the appropriate rail and wheel geometry for proper grease transfer.

Additional data processing as shown in Exhibit 6 revealed another segment of gauge face wear that is variable to operating conditions, the vertical striped segment of each bar at each location. This segment is wear from conditions beyond the response range of the trackside lubricator/grease com- bination. These variations include weather, operational limitations of lubricator equipment, grease properties, maintenance intervals, and train operations that do not match the track plan. The 22% wear due to variable operating conditions in the 9-degree curve (at point 9.5R, V298.3) is heavily related to train movements below planned track speed (underbalanced). A signal is positioned 100 yards prior to the trackside lubricator at V298.5 and STOP signals are common at this location. The 16% wear due to variable operating conditions in the 4-degree curve (at point 4R, V296.0) is more related to factors that influence the grease carry.

The remaining segment, the top part of each bar at each location, of gauge face wear is perma- nent potential savings. The application of proper equipment and compatible grease reduces gauge face wear. The average wear reduction for the test track is 63% or 0.1623 inches per 100 MGT.

The natural question this information generates from anyone dealing with a budget is "How much money does it save?" To simplify and bring to a common denominator, this pie chart (Exhibit 7) shows wear segment comparisons with lubrication conditions defined as AAR Dry Rail (0.5 inches/ lOOMGT). For each dollar of rail gauge face wear cost per 100 MGT, the cost per segment is reflected by the related percentage noted. The potential savings, assuming dry rail conditions initially, are 81.71 cents per dollar of your actual rail gauge face wear cost based on new rail cost FOB plant. Note that, if the rail is profile ground more than once per 100 MGT, the additional cost of grind wear must be deducted from potential savings. This savings prediction is conservative. AAR Dry Rail is defined as a wear range of 0.5 - 0.7 inches per 100 MGT. All calculations were based on 0.5 inches per 100 MGT. Your dry rail wear may be greater than reflected in this analysis.

The next quesfion expected is "How did you do it?" We had to learn that our trackside lubrica- tion arrangements were not performing to expectations:

1. Each passing wheel is not lubricated by current designs of trackside lubricators. In cold weather, 30-45 cars must pass before the lubrication system is adequately pressurized to sup- ply grease through the wiping bar ports.

2. There are great efficiency differences among actuator/pump designs. The design that best provides constant grease pressure results in less waste grease.

3. Grea.se formulations must be compatible with the equipment operation. The physical char- acteristics of the grease after being pumped through the lubricator system must support the formation of a grease column at the wiping bar port that transfers the grea,se to the passing wheel flange. New grease formulations were developed for NS applications.

72

Bulletin 760 — American Railway Engineering Association

in d

S3H0NI 'dV3/\A 3AllVini/\in00V

Exhibit 5

Rail Gauge Face Wear Rate Per 100 MGT

Test Site MP V298.5-V295.7

Paper by D. E. Creeger

73

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ioi/M-ooi /S3H0NI 'av3M 3Aiivnni/Mnoov

Exhibit 6

NS Semi-Dry Rail

Gauge Face Wear Components

74

Bulletin 760 — American Railway Engineering Association

POTENTIAL SAVINGS

(81.71%)

(3.50%) tif^^ (8.56%)

Lubricated Wear

Profile Grind & Wear

Variable Operating Conditions

Loss Without Improvements

Exhibit 7 Wear Cost/100 MGT with AAR Dry Rail Curves > 3.5-Deg at Mill Cost Net Scrap

TABLE 2: *WIPING BAR - PORT DESIGN

PERFORMANCE:	LARGE PORT	SMALL PORT	BLOCKS
Grease Carry Distance in Test Site, AVG % of Site Protected	48.2	100	69.2
Waste Grease Collected (2 wheel turns), %, range with various arr£ingements	24.4-38.0	10.1-32.0	75.5
Grease Consumed, Pounds/ MGT-Mile	46.0	15.2	92.4

♦Portec MC-3 wiping bars were modified to small ports and compared to the standard MC-3 design.

Exhibit 8

TABLE 3 ; LUBRICATOR ARRANGEMENT PERFORMANCE COMPARISON

SUPPLIER	RATING
A	45
B	59
C	72
D	96

Exhibit 9

Paper by D. E. Creeger

75

4. Wiping bar design is critical to successful track gauge face lubrication (Exhibit 8). Portec MC-3 wiping bars were compared with M&S Blocks and modified MC-3 wiping bars. The modified bars were equipped with a manifold divider that decreased the port size and dou- bled the number of ports. The test site was monitored for the amount of grease consumed, waste grease collected at the lubricator site, and grease carry distance. These data were processed to include all the parameters of each setup for a direct comparison (Ibs/MGT-mile) of grease used per MGT of traffic movement for one mile. The small port design performed better than the .standard MC-3 design by a factor of 3X and 6X better than M&S Blocks. Note that the grease must be compatible with the lubricator equipment.

After good lubrication patterns had been established and maintained, various suppliers' equip- ment arrangements and mixtures of suppliers' equipment were comparison tested in actual service. A rating system (Exhibit 9) was developed from the many measured parameters deemed important to NS operations. Equipment arrangement performance was found to have a very large range.

In conclusion, we at Norfolk Southern view proper trackside lubrication as a continuing source of opportunity. The work we have done only improves the performance of old technology. We are hopeful that the 21st century brings us lubrication methods representative of current and future tech- nology.

Reference

Elkins, J. A., Reiff, R.P., and Rhine P.E., "Measurement of Lubrication Effectiveness", 1984.

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THE PHILOSOPHY AND DEVELOPMENT OF AREA SEISMIC DESIGN CRITERIA

By: Kenneth L. Wammel*, Zolan Prucz** and Roger S. Boraas***

Abstract

Formulation of seismic design criteria for railroads, as part of the American Railway Engi- neering (AREA) Manual of Standard Practice, is a recent and ongoing development. The philosophy of railroad managements regarding post seismic event disruptions to operations and acceptable struc- tural damage can differ from that of highway departments or other public agencies. The objective of AREA Committee 9 is to establish a performance based approach to seismic design of railroad struc- tures, that incorporates three levels of ground motion and considers the ability of railroads to control post seismic event operations.

Introduction

For several decades, earthquake related damage has received significant attention. Seismic events can and have occurred in most areas of North America. In particular, the western United States continues to experience noticeable seismic events almost on a daily basis. Some highway and build- ing failures have been extensive, with many fatalities. This has prompted considerable interest within the engineering profession and has triggered political interest and some legislation.

During past earthquakes, railway structures have generally performed very well with a few bridges suffering major damage but most receiving only minor, superficial or no damage. However, becau.se of the attention given to highway failures, railroad .structural survival was generally over- looked until recently. Public agencies have been pressuring railroads into incorporating seismic designs, for new con.struction and retrofit applications, based on highway criteria. In some cases, leg- islation has been pas.sed mandating various seismic designs be implemented into railroad structures. Railroad bridge engineers have always been vitally interested in maintaining reliability in their infra- structure to ensure safety of passengers, customers' goods, employees and the public at large. The dif- ference in response of highway and railroad structures to earthquake forces promoted considerable debate on the application of engineering principles to designs. But, until recently, almo.st no research had been conducted to study railroad structural behavior The fact that railroad structures have his- torically survived seismic events, when adjacent highway .structures failed completely, has not been adequately considered in addressing new design requirements.

Typical railroad bridges in North America are very simple in their design and construction. They have relatively short spans and large pier or cap top areas that allow for considerable longitu- dinal and lateral movements. The design live load to dead load ratio, for railroad bridges, is signifi- cantly higher than live load to dead load ratios for other bridge .structures. The longitudinal and lat- eral design load requirements provide for a strong and stiff structure. In addition, the track structure provides longitudinal continuity over piers and abutments that restrains and dampens superstructure longitudinal movements. Railroad bridge designs are usually not restricted by geometric constraints, as are highway interchange bridges for example, and their configurations are mainly based on struc- tural and functional criteria.

The performance requirements for railroad bridges, such as the acceptable damage and restora- tion of service time, can vary with the bridge type, location, replacement value, inspection and main-

* Chic!' Engineer .Structures, Union Pacific Railroad, Omaha. NE.

* A.s.sociatc. Modjcski and Ma,stcr.s. Inc.. New Orlcan.s. LA "Diivclor .StiTjctures Design. Union Pacific RaiUoad. Omaha. NE

77

78 Bulletin 760 — American Railway Engineering Association

Icnance procedures, detour availability, type of service and bridge occupancy rate. For example, depending on train speed and operating practices of a particular railroad, vertical and/or lateral dis- placement of a few inches could be within acceptable limits.

Most railroad bridges have a very low live load occupancy rate (typically less than 5% for a heavy haul line). A centralized signal and communication .system that can control train movements allows for an effective railroad post seismic event response. Warning systems such as motion detec- tors, inclinometers and other devices may also be tied in to the signal system to assi.st in determining the need for in.spections and/or train movement restrictions. Some railroads have connections with various .seismic and geological centers that provide early data on seismic activities. The low occu- pancy rate and the ability of the railroad to stop or reduce the speed of traffic over a particular seg- ment of track until inspections are made are important factors, unique to railroad bridges, that need to be incorporated in the seismic design and evaluation criteria.

In 1994, a group of "volunteers", from the AREA structural committees, met to discuss the issue of seismic design of railroad structures. The AREA Manual did not address the issue and there was interest among railroad engineers and designers of railroad structures to understand the historical record of bridge response to seismic events. Also, there were increasing pressures from some gov- ernmental agencies for railroads to accept seismic designs and retrofits based on highway bridge characteristics and research. This ad-hoc committee produced a general basis for what is now Chapter 9. Committee 9 was formed to further develop and refine the ad-hoc committee's work.

Performance Based Approach to Seismic Design

The purpose of Chapter 9 is to provide a framework to evaluate the effect of seismic forces on railroad bridge structures and help reduce damage to railway facilities. The objectives were estab- lished as follows:

1. Evaluate past experience.

2. Develop post seismic event operation procedures based on historical precedent and compat- ible with structure performance.

3. Establish well-defined performance requirements that account for the unique features of rail- road structures.

4. Establish analysis requirements consistent with current methods of railroad structure evalu- ation and design.

5. Allow flexibility to address the specific condition, value and importance of a structure.

6. Provide a basis for more detailed analysis for special projects.

7. Promote research and testing to validate past experience and support any new design requirements.

8. Provide flexibility for future code updates.

To achieve these objectives, a three-level ground motion and performance criteria approach, consistent with railroad post seismic event response procedures, was developed, as shown in Table 1 .

Table 1. Three-Level Ground Motion and Performance Criteria Approach to Seismic Design

Railroad Ground Performance Methods of Analysis

Response Motion Criteria Limit Methods of Analysis

Level Level State and Detailing

II I Serviceability Elastic

III 2 Ultimate Capacity/Conceptual III 3 Survivability Conceptual

Paper by Kenneth L. Wammel, Zolan Prucz and Roger S. Boraas 79

Each ground motion level is associated with specific bridge performance requirements and a specific railroad response level. Table 1 shows the railroad response level and the performance crite- ria limit state in relation to the ground motion level. Guidelines for railroad response after an earth- quake, and analysis and design approaches for satisfying each performance criteria limit state, are recommended. The railroad response levels consider the earthquake magnitude and distance from railroad facilities and are described more fully in Chapter 9.

Ground Motion Levels

The ground motion levels reflect the seismic hazard at the site and are directly related to the design (or evaluation) earthquake loads. They are defined in terms of expected peak ground acceler- ation values associated with a given average return period. Several acceleration coefficient maps may be used to interpolate for a selected ground motion return period. The average return period for each ground motion level is determined based on acceptable risk criteria and .structure importance classi- fication, as shown in Table 2.

Table 2. Ground Motion Levels for Seismic Design

Ground Structure

Motion Acceptable Importance Return Period

Level Description Risk Criteria Classification (Years)

1 Moderate Life Safety 1-4 5-100

2 Large Economics 1-4 200-500 ^ Severe Economics 1-4 1000-2400

Ground Motion Level 1 represents a moderate earthquake with a reasonable probability of being exceeded during the life of the structure. After such an earthquake, trains may proceed at restricted speeds until inspections are completed and track released for full speed operation. Therefore, the design criteria for Ground Motion Level 1 needs to ensure that the structure is safe and serviceable immediately after the earthquake. Ground Motion Level 2 has a low probability of being exceeded during the life of the structure, and it represents a larger magnitude earthquake. Ground Motion Level 3 has a very low probability of being exceeded during the life of the structure, and it represents a rare and severe earthquake. Train traffic is stopped after both Ground Motions Levels 2 and 3 until property can be inspected, as per Railroad Response Level III. Therefore, for Ground Motion Levels 2 and 3, the performance and the acceptable risk criteria can be based mainly on eco- nomic considerations.

Acceptable Risk Criteria

Earthquakes are extreme events associated with a great amount of uncertainty and therefore risk considerations are an integral part of seismic design. The greatest source of uncertainty is associated with the regional seismicity and the expected ground motion characteristics at the site. Differences between the calculated and the actual seismic response of a structure also add to the general degree of uncertainty. To achieve a balance between seismic risk and costs associated with risk reduction, a certain amount of risk must be considered as acceptable, unless there is a severe social penalty as.so- ciated with structure failure.

When determining acceptable risk levels, both life safety and economic aspects need to be con- sidered. Obviously, the amount of risk that may be acceptable for some bridge structures is greater than for others. Factors such as the volume and the type of train traffic, the value and the importance of the bridge and the cost of loss of use have to be included. Acceptable seismic risk levels must also be con- sistent with the risks due to other extreme events, such as flood, fire and vehicle or vessel collision.

80 Bulletin 760 — American Railway Engineering Association

Structure Importance Classification

The importance classification of a structure along with the acceptable risk considerations deter- mines the average ground motion return period to be used for the evaluation of each performance cri- teria limit state. It is expressed as a factor that can vary from 1 to 4 and includes the relative contri- butions of aspects related to bridge location, traffic over and under the bridge, the value of the bridge, and detour availability. Weighting factors for these contributions are assigned to each performance limit state. They may vary to represent specific railroad and project requirements.

Structure Performance Criteria

The structure performance criteria include the following limit states: Sennceability Limit State:

The serviceability limit state contains restrictions on bridge stresses, deformations, vibrations and track misalignments due to a Level 1 Ground Motion. The structure is required to remain in the elastic range and only moderate damage, that does not affect the safety of trains at restricted speeds, is allowed.

Ultimate Limit State:

The ultimate limit state ensures overall structural integrity during a Level 2 Ground Motion. The strength and stability of critical members are of main concern. The structure is allowed to respond beyond the elastic range but displacement, ductility and detailing requirements need to be satisfied to reduce damage and loss of structure use. The damage should occur as intended in design, be readily detectable by visual inspection and accessible for repair.

Sun'ivability Limit State:

The survivability limit state is concerned with the survival of the bridge structure after a Level 3 Ground Motion. Extensive damage, short of bridge collapse, may occur. Structural and geometric safety measures, which add redundancy and ductility, are recommended to reduce the likelihood of collapse. Other measures designed to prevent collapse in case of serious damage, such as wide bear- ing support areas, catcher or backup systems, may be included. Depending on the importance and the replacement value of a bridge, an individual railroad may allow irreparable damage for the surviv- ability limit state, and opt for new construction.

Conceptual Approach to Seismic Design

Elastic analysis methods are recommended for satisfying the serviceability limit state and a conceptual approach is recommended for the ultimate and the survivability limit states. The concep- tual approach proposed consists of seismic guidelines regarding structure type, foundation type, con- figuration and layout, connections, materials, ductility, redundancy, deformation capability and fail- ure mode control. By using conceptual seismic design principles along with capacity design methods, the engineer can overcome many of the uncertainties involved in the ground motion description, the numerical analysis of structure response in the post yield range, and the limited analytical and exper- imental seismic research data on railroad bridges currently available.

Existing Bridges

The general seismic design criteria approach may be applied to existing bridges. However, some aspects are unique to existing bridges and require special consideration. First, to keep the ana- lytical efforts to a manageable size, a preliminary seismic screening is recommended to identify the most vulnerable bridges. Second, the selection of ground motion return periods, especially for Ground Motion Levels 2 and 3, should consider the age, value, load capacity and remaining service life of the bridge evaluated. Third, since the current state of knowledge of response analysis of exist- ing railroad bridges to severe ground motion is limited, field information and observations from pre- vious earthquakes are very important. Bridges selected for retrofit need to undergo a more detailed

Paper by Kenneth L. Wammel, Zolan Prucz and Roger S. Boraas

evaluation that includes the effects of the retrofit on the bridge response. The retrofits considered should address the cost-benefit of risk reduction, especially regarding the ultimate and the surviv- ability limit states.

Current Committee Assigmnents

Presently, the subcommittees of Committee 9 are working on the following topics:

• Expansion and improvement of the Structure Importance Classification section

• Expansion of design criteria for the serviceability limit state

• Expansion of conceptual approach criteria for ultimate and survivability limit states

• Definition and improvement of the preliminary screening to identify the existing bridges needing more detailed analysis

• Development of a post seismic event inspection checklist

• Development of general guidelines for retrofit designs

Recently, a new assignment "Track Contribution to Seismic Response" has been undertaken by Subcommittee 2. It is a widespread belief that the track plays an important role in the excellent earth- quake survival record of railroad bridges. However, no current design criteria allow for that consid- eration because it cannot yet be quantified. Therefore, more testing and research of the role of track (or other aspects of bridges unique or predominant to railroads) in structural resistance to seismic loads is important for further development of detailed design and evaluation criteria. Without hard data, no design formula can accurately account for the positive contribution of the track.

The Future

The committee has currently focused much of its attention on bridges. The need to understand and quantify the differences between railroad and highway bridge response to seismic loading has been the driving force behind the committee's work. But other aspects of railroad infrastructure will also be addressed. Signal and communication facilities are very susceptible to failure from seismic events. Recommended practice for design of these facilities should be included. Building failures, subgrade failures and track geometry deviations are also part of the seismic scenario. However, build- ings and subgrades are not unique to the railroad and can be covered by many current design speci- fications. Track is a very flexible structure, easily restored, and it's response is heavily dependent on the subgrade reaction. At this time, it is not anticipated that any new criteria will be developed for track design.

Recent discussions between the FRA and the Ministry of Transport of Japan may lead to an agreement for cooperative effort between the two countries. This will provide for information shar- ing and the formation of joint, engineering teams for post seismic event investigations into structural performance.

Summary

The seismic design and evaluation criteria recommended consider the unique structural and operating characteristics of railroad structures and the specific needs of railroad bridge owners. The approach used is based primarily on detailed performance requirements, and on conceptual design and detailing practices. The railroad post seismic event response procedures, along with the type and amount of acceptable damage for a given structure, are an integral part of the design and evaluation process. A three-level ground motion and performance criteria approach is employed to reduce train interruption and ensure structure serviceability after a moderate earthquake, minimize the cost of damage and loss of structure use after a large earthquake and prevent structure collapse after a very severe earthquake.

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82

FRACTURE TOUGHNESS TESTING OF AREA GRADE B HAND TOOL STEEL

By: C. P. Lonsdale* and J. J. Lewandowski**

Abstract

Fracture toughness testing was conducted on a number of railroad maintenance striking hand tools in order to determine their resistance to crack propagation in the presence of a flaw. Specimens for toughness testing were removed from different spike mauls as well as sledge hammers. In the former, four of the samples were removed from near the large end striking face of four different spike mauls. In the latter, four samples were taken from near each striking face of two different ten pound double faced sledge hammers. Samples containing a fine diamond wire saw notch established a notch tough- ness of 50.3 MPaVm (45.8 ksiVin) for one sledge sample and 66.0 MPaVm (60.1 k.siVin) for one maul sample. Fatigue precracking of the samples to produce a very fine crack prior to testing resulted in sub- stantially lower fracture toughness values. The average value for three precracked maul samples was 45.2 MPaVm (41.1 ksiVin) while the three precracked sledge samples establi.shed an average toughness of 31.5 MPaVm (28.7 ksiVin). The fracture toughness of AREA Grade B steel hand tools and some vari- ables that affect toughness is discussed. The importance of routine and reliable field tool inspections is highlighted due to the relatively low resistance of the steel to fast fracture when a crack is present.

Introduction

Sledge hammers and spike mauls are essential hand tools for track maintenance in the railroad industry. Although automated maintenance of way equipment has resulted in fewer employees now using such striking hand tools, there will always be the need for manual track repairs. Rail replace- inents, tie change outs, etc., insure that these tools will be around for many years. However, when these tools strike an off center blow, the chance of a chip or spall is greatly increased, since the impact contact area is very small and, therefore, the local stress is very high. The striking face contour, or comer radius, is particularly vulnerable to such damage. The resistance to spalling has been reported to be improved by utilizing a gentle, carefully blended contour (Ref. I).

Conrail's Technical Services Laboratory examines sledge hammers and spike mauls which fail in service. Most often these tools have been in the field for an extended period of time and have cracking or deformation evident on the striking face or comer radius. Further impact loading during the use of the tool, particularly by an off center blow, often results in the fast fracture of a steel chip. Injuries to Conrail Maintenance of Way employees resulted in our investigation of the fracture tough- ness of the steel used in North American railroad sledges and mauls.

Background

The specifications which govern railroad percussion tools are contained in Chapter 5 (Track) of the American Railway Engineering Association's Manual for Railway Engineering (Ref. 2). The steel used in striking and stmck tools must be a Grade A or Grade B chemical composition, as shown in Table I.

The more common alloy used today for sledges and spike mauls is AREA Grade B steel. This steel most closely matches the AISI 9260 designation, with vanadium and molybdenum added. The striking faces are required to have a hardness of 51 to 55 Rockwell C and this hardness specification is maintained to at least one half of an mch below the face. The tools are forged, quenched and tem- pered products produced by several manufacturers. Typical tensile test data provided by a manufac- turer and obtained on one cylindrical specimen taken from a spike maul and one cylindrical speci-

* Moiallurgical Engineer. Conrail Technical Services Laboratory. Alloona. PA. **Prole.s.sor of Materials Science and Engineering, Case Western Reserve University. Cleveland. OH.

83

S4 Bulletin 760 — American Railway Engineering Association

Table 1. AREA percussion hand tool chemistry specifications.

Steel	C	Mn	P	S	Si	V	Mo
Grade	Min Max	Min Max	Max	Max	Min Max	Min Max	Min Max
A	0.56 0.64	0.75 1 .00	0.025	0.025	1.80 2.20	— —	— —
B	0.5 1 0.60	0.75 1.00	0.025	0.025	1.80 2.20	— 0.45	0.35 0.50

men taken from a sledge hammer are contained in Table 2 (Ref. 3). The threaded end tensile speci- mens were electrodischarge machined from the steel between the tool eye and outside wall diameter for each type of tool. No comparative evaluations of steel chemistry, cleanliness, microstructure, etc., were conducted in order to explain the large differences in sledge and maul sample properties. Although our sample size is very limited (one tensile sample for each tool type), it is possible that significant differences in raw materials and/or finished tools exist. It appears that an investigation of these variables may have benefits for industry.

Scope of Evaluation

One way to determine the fracture resistance of Grade B steel involves determining the fracture toughness on specimens containing a fatigue precrack in accordance with accepted procedures for fracture toughness testing. Subsequent comparisons of these fracture toughness values with those of other steels will provide information on the range of strength/hardness/toughness values available in other commercially available high strength steels. In addition, knowledge of the fracture toughness in combination with some estimate of the applied stresses enables an estimation of the critical crack size for catastrophic fracture.

Experimental Procedure

Four new spike mauls and two new ten pound sledge hammers were obtained from a group of tools on hand at Conrail. All tools were produced by the same manufacturer, Woodings-Verona Tools Works. Three point bend fracture specimens were machined from the large end of each spike maul and from both ends of the sledges. The samples were taken from just below the center of the striking face and parallel to it in each case. The specimens were electrodischarge machined with the crack propagation direction away from the striking face center into the body of the forged tool. Examinations

	Table 2. Spike	maul and sledge hammer tensile test data.
Tool Type	Tensile Strength (psi)	Yield Strength (psi)	Percent Reduction In Area	Percent Elongation
Maul Sledge	221,000 256,000	176,000 214,000	25 18	8.5 7

Table 3. Tool and sample identification data.

Tool	Fracture Sample	I.D.	Year and Month Tool Produced
Sledge 1	lA, IB		August, 1993
Sledge 2	2A, 2B		December. 1994
Maul 1	1		October, 1995
Maul 2	2		October, 1995
Maul 3	3		October. 1995
Maul 4	4		December, 1995

Paper by C. P. Lonsdale and J. J. Lewandowski

of fractured hammers and spike mauls often show that cracks start at the comer radius adjacent to the striking face. However, it was felt that the precracked samples would provide an adequate measure- ment of the steel's toughness. Table 3 contains tool and sample identification data. The general dimensions of the four sledge hammer and four spike maul toughness specimens are shown schemat- ically in Figure I .

Prior to any testing, the sides of the specimens were polished to a mirror finish to aid in crack detection. In order to first determine an estimate of the fracture toughness, one (1) toughness speci- men of the sledge hammer and the spike maul were tested in the notched condition (i.e. no fatigue precrack) in three point bending. The notch was placed in the top surface of the toughness specimen using a slow speed diamond impregnated wire saw, producing a notch root radius of approximately 50 mm. These specimens were notched to a depth aAV of approximately 0.4. A clip gage was placed across the notch opening in order to record the notch opening displacement during testing. Tests were conducted on a servo-hydraulic testing machine operated under displacement controlled conditions at a displacement rate of 0.5 mm/min, while both the load and the notch opening displacement were recorded. At the conclusion of the test, the peak load achieved prior to catastrophic fracture was used to estimate the toughness in the manner outlined in ASTM E-399.

The remaining six sledge hammer and spike maul specimens were each notched to an aAV = 0.25-0.33 prior to fatigue precracking, in an attempt to conduct fracture toughness testing on fatigue precracked specimens, in general accordance with the procedures outlined in ASTM E-399. Notching was again conducted with the slow speed wire saw, followed by fatigue precracking in accordance with ASTM E-399. In all ca.ses, attempts were made to precrack the specimens to an aAV = 0.40-0.65, in accordance with ASTM E-399. The outside surfaces of the toughness specimens were visually monitored during precracking in order to monitor the progression of the fatigue crack. Load shedding was conducted after the crack grew a specified amount in accordance with ASTM E-399. In some cases, the specimens failed during fatigue precracking. In those cases, the fatigue precrack length was noted via optical examination of the fracture surface and the toughness was calculated using the aAV and the peak load from the fatigue test. In other cases, the specimens were success- fully precracked and the fracture toughness test was conducted in accordance with ASTM E-399. Specimens successfully fatigue precracked were tested in three point bending with a clip gage placed

:^<#ir

Figure 1. Example dimensions and diagram of fracture toughness specimens.

86 Bulletin 760 — American Railway Engineering Association

across the crack mouth in order to monitor crack opening displacement. The loading rates and test procedures were as those outlined above.

Results and Discussion

The results of the toughness testing are shown in Table 4. The data clearly show that the pres- ence of a fatigue crack in the specimens produces a lower toughness than that when a notch is pre- sent. The notch produced with the diamond wire saw provided a notch root radius of about 50 mm, which is a less severe defect than that produced by a sharp fatigue crack. As expected and as obtained on many other materials, the toughness of the sledges dropped from 50.3 MPaVm (45.8 ksiVin) with the notch to an average value of 31.5 MPaVm (28.7 ksiVin) with the fatigue precrack. The notch toughness of the mauls was 66.0 MPaVm (60.1 ksiVin) while precracked specimens again exhibited a reduced toughness value. Although the spike mauls failed during precracking, the estimated tough- ness was as low as 34.9 MPaVm (31.8 ksiVin), somewhat higher than that obtained on the sledge hammer specimens. Although it is difficult to conduct .standard ASTM tests on such specimens because of their small size and difficulty in fatigue precracking, the results obtained on the notched specimens provide an estimate of the fracture toughness, while those obtained with the sharp fatigue precrack cleady show that the toughness is reduced when a sharp crack is present.

There also appears to be a difference in both the notch toughness and precracked toughness between the sledge hammer and spike maul specimens. Assuming that identical starting material compositions are used, one potential source of this difference relates to the differences in manufac- ture of the two products. The finished spike maul section diameter on the large end (1% inches) is smaller than the finished section diameter of the ten pound sledge (2'/: inches). A review of the man- ufacturing process reveals that mauls are forged from a 2 inch diameter round bar whereas ten pound sledges are forged from 2Vi inches diameter round stock (Ref. 3). As such the reduction applied to the former material during forging is much greater than that applied to the latter. One manufacturer reported that a ten pound sledge receives only two forging blows during manufacture while a spike maul receives eight to ten forging blows (Ref. 3). Such differences in forging reduction could produce beneficial changes to the microstructure in the spike mauls that would affect the strength/toughness of the quenched and tempered material. The subsequent heat treatment of such tools and their different dimensions also produces a final hardness profile which is somewhat different for the two products, while changes to the tempering treatments could also produce changes to strength/toughness combi- nations possible in such materials. The spike mauls which contain the smaller section size should exhibit a more uniform microstructure and a high hardness should be maintained to a greater percent- age of the tool cross-section if both products were given an identical quench, prior to tempering.

Table 4. Results of fracture toughness testing.

				Toughness
Tool Type	Sample I.D.	Notch/Precrack	Mpa Vm	ksi Vin
Sledge 1	lA		Notch	50.3	45.8
Sledge 1	IB		Precrack*	30.5	27.8
Sledge 2	2A		Precrack	28.9	26.3
Sledge 2	2B		Precrack	35.1	31.9
Average Value	For Precracked Slec	ge Samples		31.5	28.7
Maul 1	1		Notch	66.0	60.1
Maul 2	2		Precrack*	34.9	31.8
Maul 3	3		Precrack*	52.6	47.8
Maul 4	4		Precrack*	48.1	43.7
Average Value	For Precracked Mai	1 Samples		45.2	41.1

Note: *Failed during precracking.

Paper b\ C. P. Lonsdale and J.J. Lewandovvski

87

Figure 2 shows the macroetched structure of a commercial Grade B steel railroad spike maul which has been longitudinally sectioned (Ret'. 3). The top maul section is From the small end ( 1 % inches striking face diameter) while the bottom section is from the large end (1% inches diameter). The amount of visible centerline segregation is clearly greater in the larger end section. The smaller end that obtained more mechanical working during forging, does not exhibit a pronounced centerline streak. Such segregation, which results from solidification of the steel raw stock could then affect the frac- ture properties of railroad hand tools if such regions are loaded under high stress conditions. Such sites could be preferential sites for both crack initiation and growth.

The estimates of precracked fracture toughness values reported in Table 4 enable one to esti- mate the combinations of stress and crack size which will produce catastrophic fracture in a struc- ture. In the case of the materials examined presently, it is assumed that a crack propagates inward from the surface of the hammer or spike maul in the manner approximated by the fracture toughness specimens tested. The general relation between the fracture toughness and the combinations of stress and crack size required to produce catastrophic fracture is summarized in the following equation:

Kn = geometric factor x ct ( IT a)

where K^ is the fracture toughness, a is the applied stress, and a is the crack length. Since this calculation is provided presently as an estimate, the geometric factor will be set equal to 1 . The equa- tion indicates that, for a given level of fracture toughness, an increase in the applied stress will reduce the critical flaw size for catastrophic fracture. The equation also indicates that an increase in the crack size present in a structure will reduce the stress that can be applied to the structure prior to cata- strophic fracture. As an example, assuming that a tensile stress equal to the yield strength of the tool material (e.g. 176 ksi) was applied to a tool material with toughness of approximately 33 MPaVm (30 ksi\'in). the critical flaw size required for catastrophic fracture would be approximately 0.24 mm

Figure 2. Macroetched spike maul.

88 Bulletin 760 — American Railway Engineering Association

(0.00925 inches). Although the magnitude of the flaw size obtained by such a calculation will be affected by a number of variables beyond the scope of this report, it is clear that the combinations of stress and toughness cho.sen in the calculation produce a relatively small flaw size that is required for catastrophic fracture. This further suggests that frequent and careful inspections for such flaws before and after u.se might be beneficial in preventing chip spallation during use.

The