TCRP OVERSIGHT AND PROJECT SELECTION COMMISSION^*

CHAIR

Jeanne Krieg

Eastern Contra Costa Transit Authority (retired)

VICE CHAIR

Jameson Auten

Lane Transit District

SECRETARY/TREASURER

Ryan I. Daniel

St. Cloud Metro Bus

IMMEDIATE PAST CHAIR

Doran J. Barnes

Foothill Transit

MEMBERS

Andrea Burnside

Washington Metropolitan Area Transit Authority

Julia Castillo

Heart of Iowa Transit Authority

April Chan

San Mateo County Transit District

Desmond Cole

Southeastern Pennsylvania Transportation Authority

Carolyn Flowers

InfraStrategies LLC

David Harris

New Mexico Department of Transportation

Tim Healy

Sound Transit

Brendon Hemily

Hemily and Associates

Vince Huerta

East Texas Council of Governments

Joseph Leader

HDR

Benjamin Limmer

Connecticut Department of Transportation

Bacarra Mauldin

Memphis Area Transit Authority

Jessica Mefford-Miller

Valley Metro

Raymond Melleady

USSC Group

Brad Miller

Pinellas Suncoast Transit Authority (PSTA)

Elizabeth Presutti

Charlotte Area Transit System

Catherine Rinaldi

MTA Metro North Railroad, NY

Jeffrey Rosenberg

Amalgamated Transit Union

Bernard Schmidt

NextEra Energy

Justin Stuehrenberg

Madison Metro Transit

Frank White, III

Kansas City Area Transportation Authority

Kimberly J. Williams

Metropolitan Transit Authority of Harris County

Nigel H.M. Wilson

MIT

EX OFFICIO MEMBERS

Shailen Bhatt

FHWA

Victoria Sheehan

TRB

Paul P. Skoutelas

APTA

Jim Tymon

AASHTO

Veronica Vanterpool

FTA

TOPS COMMISSION STAFF ADVISOR

Arthur L. Guzzetti

APTA

SECRETARY

Monique R. Evans

TRB

___________________

^* Membership as of August 2024.

TRANSPORTATION RESEARCH BOARD 2024 EXECUTIVE COMMITTEE^*

OFFICERS

CHAIR: Carol A. Lewis, Professor, Transportation Studies, Texas Southern University, Houston

VICE CHAIR: Leslie S. Richards, General Manager, Southeastern Pennsylvania Transportation Authority (SEPTA), Philadelphia

EXECUTIVE DIRECTOR: Victoria Sheehan, Transportation Research Board, Washington, DC

MEMBERS

Michael F. Ableson, CEO, Arrival Automotive–North America, Detroit, MI

James F. Albaugh, President and CEO, The Boeing Company (retired), Scottsdale, AZ

Carlos M. Braceras, Executive Director, Utah Department of Transportation, Salt Lake City

Douglas C. Ceva, Vice President, Customer Lead Solutions, Prologis, Inc., Jupiter, FL

Nancy Daubenberger, Commissioner of Transportation, Minnesota Department of Transportation, St. Paul

Marie Therese Dominguez, Commissioner, New York State Department of Transportation, Albany

Garrett Eucalitto, Commissioner, Connecticut Department of Transportation, Newington

Chris T. Hendrickson, Hamerschlag University Professor of Engineering Emeritus, Carnegie Mellon University, Pittsburgh, PA

Randell Iwasaki, President and CEO, Iwasaki Consulting Services, Walnut Creek, CA

Ashby Johnson, Executive Director, Capital Area Metropolitan Planning Organization (CAMPO), Austin, TX

Joel M. Jundt, Secretary of Transportation, South Dakota Department of Transportation, Pierre

Hani S. Mahmassani, W.A. Patterson Distinguished Chair in Transportation; Director, Transportation Center, Northwestern University, Evanston, IL

Scott C. Marler, Director, Iowa Department of Transportation, Ames

Ricardo Martinez, Adjunct Professor of Emergency Medicine, Emory University School of Medicine, Decatur, GA

Michael R. McClellan, Vice President, Strategic Planning, Norfolk Southern Corporation, Atlanta, GA

Russell McMurry, Commissioner, Georgia Department of Transportation, Atlanta

Craig E. Philip, Research Professor and Director, VECTOR, Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN

Steward T.A. Pickett, Distinguished Senior Scientist, Cary Institute of Ecosystem Studies, Millbrook, NY

Susan A. Shaheen, Professor and Co-director, Transportation Sustainability Research Center, University of California, Berkeley

Marc Williams, Executive Director, Texas Department of Transportation, Austin

EX OFFICIO MEMBERS

Michael R. Berube, Deputy Assistant Secretary for Sustainable Transportation, U.S. Department of Energy, Washington, DC

Shailen Bhatt, Administrator, Federal Highway Administration, U.S. Department of Transportation, Washington, DC

Amit Bose, Administrator, Federal Railroad Administration, Washington, DC

Tristan Brown, Deputy Administrator, Pipeline and Hazardous Materials Safety Administration, U.S. Department of Transportation, Washington, DC

Steven Cliff, Executive Officer, California Air Resources Board, Sacramento

Rand Ghayad, Senior Vice President, Association of American Railroads, Washington, DC

LeRoy Gishi, Chief, Division of Transportation, Bureau of Indian Affairs, U.S. Department of the Interior, Germantown, MD

William H. Graham, Jr. (Major General, U.S. Army), Deputy Commanding General for Civil and Emergency Operations, U.S. Army Corps of Engineers, Washington, DC

Robert C. Hampshire, Deputy Assistant Secretary for Research and Technology, U.S. Department of Transportation, Washington, DC

Zahra “Niloo” Parvinashtiani, Engineer, Mobility Consultant Solutions, Iteris Inc., Fairfax, VA, and Chair, TRB Young Members Coordinating Council

Sophie Shulman, Deputy Administrator, National Highway Traffic Safety Administration, Washington, DC

Karl Simon, Director, Transportation and Climate Division, U.S. Environmental Protection Agency, Washington, DC

Paul P. Skoutelas, President and CEO, American Public Transportation Association, Washington, DC

Polly Trottenberg, Deputy Secretary of Transportation, U.S. Department of Transportation, Washington, DC

Jim Tymon, Executive Director, American Association of State Highway and Transportation Officials, Washington, DC

Veronica Vanterpool, Acting Administrator, Federal Transit Administration, Washington, DC

Michael Whitaker, Administrator, Federal Aviation Administration, U.S. Department of Transportation, Washington, DC

Vinn White, Deputy Administrator, Federal Motor Carrier Safety Administration, Washington, DC

TRANSIT COOPERATIVE RESEARCH PROGRAM

The nation’s growth and the need to meet mobility, environmental, and energy objectives place demands on public transit systems. Current systems, some of which are old and in need of upgrading, must expand service area, increase service frequency, and improve efficiency to serve these demands. Research is necessary to solve operating problems, adapt appropriate new technologies from other industries, and introduce innovations into the transit industry. The Transit Cooperative Research Program (TCRP) serves as one of the principal means by which the transit industry can develop innovative near-term solutions to meet demands placed on it.

The need for TCRP was originally identified in TRB Special Report 213—Research for Public Transit: New Directions, published in 1987 and based on a study sponsored by the Urban Mass Transportation Administration—now the Federal Transit Administration (FTA). A report by the American Public Transportation Association (APTA), Transportation 2000, also recognized the need for local, problem-solving research. TCRP, modeled after the successful National Cooperative Highway Research Program (NCHRP), undertakes research and other technical activities in response to the needs of transit service providers. The scope of TCRP includes various transit research fields including planning, service configuration, equipment, facilities, operations, human resources, maintenance, policy, and administrative practices.

TCRP was established under FTA sponsorship in July 1992. Proposed by the U.S. Department of Transportation, TCRP was authorized as part of the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA). On May 13, 1992, a memorandum agreement outlining TCRP operating procedures was executed by the three cooperating organizations: FTA; the National Academies of Sciences, Engineering, and Medicine, acting through the Transportation Research Board (TRB); and APTA. APTA is responsible for forming the independent governing board, designated as the TCRP Oversight and Project Selection (TOPS) Commission.

Research problem statements for TCRP are solicited periodically but may be submitted to TRB by anyone at any time. It is the responsibility of the TOPS Commission to formulate the research program by identifying the highest priority projects. As part of the evaluation, the TOPS Commission defines funding levels and expected products.

Once selected, each project is assigned to an expert panel appointed by TRB. The panels prepare project statements (requests for proposals), select contractors, and provide technical guidance and counsel throughout the life of the project. The process for developing research problem statements and selecting research agencies has been used by TRB in managing cooperative research programs since 1962. As in other TRB activities, TCRP project panels serve voluntarily without compensation.

Because research cannot have the desired effect if products fail to reach the intended audience, special emphasis is placed on disseminating TCRP results to the intended users of the research: transit agencies, service providers, and suppliers. TRB provides a series of research reports, syntheses of transit practice, and other supporting material developed by TCRP research. APTA will arrange for workshops, training aids, field visits, and other activities to ensure that results are implemented by urban and rural transit industry practitioners.

TCRP provides a forum where transit agencies can cooperatively address common operational problems. TCRP results support and complement other ongoing transit research and training programs.

TCRP RESEARCH REPORT 246

Project C-24

ISSN 2572-3782

ISBN 978-0-309-71003-9

Digital Object Identifier: doi.org/10.17226/27907

© 2024 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trademarks of the National Academy of Sciences. All rights reserved.

COPYRIGHT INFORMATION

Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein.

Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, APTA, FAA, FHWA, FTA, GHSA, or NHTSA endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP.

NOTICE

The research report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the National Academies of Sciences, Engineering, and Medicine.

The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; or the program sponsors.

The Transportation Research Board does not develop, issue, or publish standards or specifications. The Transportation Research Board manages applied research projects which provide the scientific foundation that may be used by Transportation Research Board sponsors, industry associations, or other organizations as the basis for revised practices, procedures, or specifications.

The Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; and the sponsors of the Transit Cooperative Research Program do not endorse products or manufacturers. Trade or manufacturers’ names or logos appear herein solely because they are considered essential to the object of the report.

Published research reports of the

TRANSIT COOPERATIVE RESEARCH PROGRAM

are available from

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The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, nongovernmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president.

The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. John L. Anderson is president.

The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president.

The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The National Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine.

Learn more about the National Academies of Sciences, Engineering, and Medicine at www.nationalacademies.org.

The Transportation Research Board is one of seven major program divisions of the National Academies of Sciences, Engineering, and Medicine. The mission of the Transportation Research Board is to mobilize expertise, experience, and knowledge to anticipate and solve complex transportation-related challenges. The Board’s varied activities annually engage about 8,500 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation.

Learn more about the Transportation Research Board at www.TRB.org.

COOPERATIVE RESEARCH PROGRAMS

CRP STAFF FOR TCRP RESEARCH REPORT 246

Monique R. Evans, Director, Cooperative Research Programs

Waseem Dekelbab, Deputy Director, Cooperative Research Programs

Gwen Chisholm Smith, Manager, Transit Cooperative Research Program

Stephan A. Parker, Senior Program Officer (retired)

Stephanie L. Campbell-Chamberlain, Senior Program Assistant

Natalie Barnes, Director of Publications

Heather DiAngelis, Associate Director of Publications

Doug English, Senior Editor

TCRP PROJECT C-24 PANEL
Field of Engineering of Vehicles and Equipment

Karl W. Berger, Berger Engineering, Centreville, VA (Chair)

Steven D. Bezner, Rockville, MD

Norma De La Garza-Navarro, N2 LLC, Dripping Springs, TX

John Jenifer, Washington Metropolitan Area Transit Authority, Washington, DC

Gordon D. Proctor, Gordon Proctor & Associates, Inc., Dublin, OH

Edward J. Rowe, LTK Engineering Services, Inc., Seattle, WA

Louis F. Sanders, Stevensville, MD

David F. Thurston, Canadian Pacific Railway Company, Calgary, AB

AUTHOR ACKNOWLEDGMENTS

The research reported herein was performed under TCRP Project C-24, “Transit Traction Power Cables: Replacement Guidelines.” Eastern Michigan University (EMU) was the contractor for the research. Dr. Kasim Korkmaz, Associate Professor at EMU, was the Principal Investigator. During the data collection process, those in the traction power industry provided continuous support. The researchers would like to acknowledge the assistance of the transit industry personnel that made this research possible. For the survey/interviews and case studies, agencies generously shared their experiences and practices.

FOREWORD

By Gwen Chisholm Smith

Staff Officer

Transportation Research Board

TCRP Research Report 246: Transit Traction Power Cables: Replacement Guidelines presents current practices for assessing insulation aging and replacement of cables before failure, including approaches used in transit systems for which there are no monitoring programs or testing systems. The guidelines present factors that affect the life of cables and effective practices from transit agencies. The guidelines will be helpful to construction managers; safety regulators; civil, electrical, and systems engineers; maintenance directors; track design practitioners; transit agencies; consultants; and other stakeholders involved in replacing transit traction power cables.

Many transit agencies’ conductor insulation systems used for traction power cables and lower voltage power distribution and signal communication systems typically have a 30-year lifespan, and many of these systems are at that age or older. Many cables within transit tunnels have had failures because of the water penetration through and around the cable insulation, causing damage to the insulation and corrosion of the copper conductor. In some subway tunnels, the conduits have degraded, so they cannot be cleaned and reused for their original purpose. Transit systems have experienced cable fires and system-wide closures due to traction power cable insulation degradation. Environmental conditions such as natural disasters exacerbate cable life-cycle concerns regarding remaining useful life. In recent years, major storms affecting the United States have inundated transit tunnels with fresh and contaminated water.

Under the TCRP Project C-24, “Transit Traction Power Cables: Replacement Guidelines,” Eastern Michigan University was asked to document relevant standards and current practices through case studies covering maintenance practices from a mix of small, large, old, and new transit systems by engaging industry subject-matter experts experienced in the design, construction, maintenance, and operation of traction power systems. They were also asked to review cable monitoring systems, such as monitors that measure cable conductor-to-earth ground resistance trends. The research team, led by Dr. Kasim Korkmaz, built on the research results documented in TCRP Web-Only Document 77: Developing a Guide for Transit Traction Power Cables to develop the guidelines.

In addition to the guidelines, products of this research include (1) the conduct of research report, published as TCRP Web-Only Document 77, which documents the development of the guidelines, including a review of the relevant literature and an assessment of the state of the practice of replacing transit traction power cables, and is available on the National Academies Press website (nap.nationalacademies.org); (2) a PowerPoint presentation that

CONTENTS

Summary

Chapter 1 Introduction

1.1 Guide Structure

1.2 Background

Chapter 2 Answers to Key Questions

2.1 Useful Life of Cables

2.2 Degree of Degradation

2.3 Detecting Degradation of Cables

2.4 Factors Influencing the Lifespan

2.5 Cost-Effective Methods to Extend the Lifespan

2.6 Smart Replacement Strategies

2.7 Installation Concerns

2.8 Cable Failure Process

2.9 Conclusions

Chapter 3 Survey and Interviews

3.1 Survey Description/Questions and Responses

3.2 Statistical Analysis

3.3 Model Analysis

3.4 Selected Responses from the Survey

3.5 Conclusions

Chapter 4 Case Studies

4.1 Case Study Structure

4.2 Case Study 1: Greater Cleveland Regional Transit Authority

4.3 Case Study 2: New Orleans Regional Transit Authority

4.4 Case Study 3: Bay Area Rapid Transit

4.5 Case Study 4: New York City Transit

4.6 Case Study 5: Amtrak

4.7 Case Study 6: Tri-County Metropolitan Transportation District of Oregon

4.8 Case Study 7: Utah Transit System

4.9 Case Study 8: Maryland Transit Administration

4.10 Case Study 9: Washington Metropolitan Area Transit Authority

4.11 Case Study 10: Metro Transit

4.12 Conclusions

Chapter 5 Cable Replacement

5.1 Cable Degradation Estimation for the Optimization Model

5.2 Optimization Model for Cable Maintenance and Replacement

5.3 Cable Failure Rate Estimation

5.4 Optimal Replacement Period