TCRP OVERSIGHT AND PROJECT SELECTION COMMISSION^*

CHAIR

Jameson Auten

Lane Transit District

VICE CHAIR

Ryan I. Daniel

St. Cloud Metro Bus

SECRETARY/TREASURER

Brad Miller

Pinellas Suncoast Transit Authority (PSTA)

IMMEDIATE PAST CHAIR

Jeanne Krieg

Eastern Contra Costa Transit Authority (retired)

MEMBERS

Rashidi Barnes

Eastern Contra Costa Transit Authority

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

David Harris

New Mexico Department of Transportation

Tim Healy

Sound Transit

Brendon Hemily

Hemily and Associates

Vince Huerta

East Texas Council of Governments

Debra Johnson

Denver Regional Transportation District

Joseph Leader

HDR

Benjamin Limmer

Connecticut Department of Transportation

Bacarra Mauldin

Edward Kizeto, LLC

Jessica Mefford-Miller

Valley Metro

Raymond Melleady

USSC Group

Meghan Merritt

Movitas Mobility

Karen Philbrick

Mineta Transportation Institute, San Jose State University

Elizabeth Presutti

Charlotte Area Transit System

Charles Reeves

Pittsburgh Regional Transit

Catherine Rinaldi

Consultant

Jeffrey Rosenberg

Amalgamated Transit Union

Judy Shanley

Easterseals

Frank White, III

Kansas City Area Transportation Authority

EX OFFICIO MEMBERS

Tariq Bokhari

FTA

Victoria Sheehan

TRB

Gloria Shepherd

FHWA

Paul P. Skoutelas

APTA

Jim Tymon

AASHTO

TOPS COMMISSION STAFF ADVISOR

Arthur L. Guzzetti

APTA

SECRETARY

Monique R. Evans

TRB

_________________________

^* Membership as of August 2025.

TRANSPORTATION RESEARCH BOARD 2025 EXECUTIVE COMMITTEE^*

OFFICERS

CHAIR: Leslie S. Richards, Professor of Practice, University of Pennsylvania, Philadelphia

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

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

MEMBERS

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

Andrew Fremier, Executive Director, Metropolitan Transportation Commission, San Francisco, CA

Martha Grabowski, Professor Emerita, Information Systems, Le Moyne College, Madden College of Business & Economics, Cazenovia, NY

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

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

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

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

Bryan Bedford, Administrator, Federal Aviation Administration, Washington, DC

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

Tariq Bokhari, Acting Administrator, Federal Transit Administration, Washington, DC

Steven G. Bradbury, Deputy Secretary, U.S. Department of Transportation, Washington, DC

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

Drew Feeley, Acting Administrator, Federal Railroad Administration, Washington, DC

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

Firas Ibrahim, Director, Office of Research, Development, and Technology, Office of the Assistant Secretary for Research and Technology (OST-R), Washington, DC

Jason Kelly, Deputy Commanding General for Civil Works and Emergency Operations, U.S. Army Corps of Engineers, Washington, DC

Sandra Knight, President, WaterWonks, LLC, Washington, DC

Ben Kochman, Acting Administrator, Pipeline and Hazardous Materials Safety Administration, Washington, DC

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

Gloria Shepherd, Acting Deputy Administrator, Federal Highway 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

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

Sang Yi, Acting Administrator, U.S. Maritime Administration, Washington, DC

_________________________

^* Membership as of August 2025.

TRANSIT COOPERATIVE RESEARCH PROGRAM

TCRP RESEARCH REPORT 257

Determination of Actual Derailment Loads on Transit Bridges

Robert A. MacNeill

Nicholas D. Catella

Sean Hsieh

Kareem Eltouny

Simpson Gumpertz & Heger, Inc.

Waltham, MA

Subject Areas

Public Transportation • Bridges and Other Structures • Passenger Transportation

Research sponsored by the Federal Transit Administration in cooperation with the American Public Transportation Association

2025

TRANSIT COOPERATIVE RESEARCH PROGRAM

The nationʼs 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 257

Project D-24
ISSN 2572-3782
ISBN 978-0-309-59972-6

© 2025 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 originality and accuracy 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.

The National Academy of Sciences (NAS) grants permission to reproduce written material in this publication for classroom and non-commercial purposes subject to the rights of any third parties and appropriate attribution. Permission is given with the understanding that none of the material will be used to imply NAS, TRB, AASHTO, APTA, FAA, FHWA, FTA, GHSA, or NHTSA endorsement of a particular product, method, or practice. For other uses of the written material, users must request permission from the National Academies Press.

Cover photo credit: Pexels.com

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.

This document is disseminated under the sponsorship of the U.S. Department of Transportation, FTA, in the interest of information exchange. The U.S. government assumes no liability for the contents or use thereof. Any opinions, findings, and conclusions or recommendations expressed or implied in this document 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 manufacturersʼ names or logos appear herein solely because they are considered essential to the object of the report.

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TRANSIT COOPERATIVE RESEARCH PROGRAM

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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. Tsu-Jae Liu 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 Boardʼs 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 departments of transportation, 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 257

Monique R. Evans, Director, Cooperative Research Programs

Waseem Dekelbab, Deputy Director, Cooperative Research Programs

Gwen Chisholm Smith, Manager, Transit Cooperative Research Program

Mariela Garcia-Colberg, Senior Program Officer

Stephanie L. Campbell-Chamberlain, Senior Program Assistant

Natalie Barnes, Director of Publications

Dominique Williams, Editor

TCRP PROJECT D-24 PANEL
Field of Engineering of Fixed Facilities

John A. Lobo, HDR, Denver, CO (Chair)

Kevin Bergthold, Metra, Chicago, IL

Anamaria Bonilla, MTA Metro North Railroad, New York, NY

Alan S. Buchanan, Southeastern Pennsylvania Transportation Authority, Philadelphia, PA

Monique Hite Head, University of Delaware, Newark, DE

Hok Lai, San Francisco Bay Area Rapid Transit, Oakland, CA

Johnathan A. Terrazas, Omega Engineers. Inc, Austin, TX

John Yao, Los Angeles County Transportation Authority, Los Angeles, CA

FOREWORD

By Mariela Garcia-Colberg
Staff Officer
Transportation Research Board

TCRP Research Report 257: Determination of Actual Derailment Loads on Transit Bridges provides the transit industry with a reasoned basis for derailment loads on bridges. It also offers methodologies that bridge design engineers can utilize to calculate the horizontal and vertical derailment impact loading. The report was developed by conducting a literature review, researching common derailment scenarios, and conducting numerical simulations of train car derailments on bridges. This report will provide bridge designers with the information they need to determine the derailment loads on transit bridges in the vertical and lateral directions.

Derailment loads in nearly all U.S. transit design criteria documents are similar across agencies. Various agencies modified these loads between 1985 and 2005 with no supporting documents or rationale. Currently, the vertical impact load is defined as 100% of the carʼs weight acting on a single truck, while the horizontal derailment load is set at 40% of the carʼs weight, also acting on a single truck. Both are assumed to cause a maximum lateral excursion of 3 feet, implying that a derailed vehicle will not travel farther. Neither one of these loads has been experimentally validated and appears to be based on an arbitrary definition that has become the standard practice in the United States. It is unclear whether the horizontal derailment load is reasonably accurate, overly conservative, or too liberal.

Under TCRP Project D-24, “Determination of Actual Derailment Loads on Transit Bridges,” Simpson Gumpertz & Heger, Inc., was tasked with formulating a rational load within the acceptable limits of accuracy to ensure the efficient and safe design of bridges by (1) selecting a representative vehicle or vehicles, (2) analyzing typical track configurations, (3) utilizing numerical modeling, (4) validating the derailment loading model that assumes loads on a single truck, and (5) establishing derailment load criteria that complement the AASHTO LRFD Guide Specifications for Bridges Carrying Light Rail Transit Loads.

The objective of this research was to determine accurate horizontal and vertical derailment loads for the efficient and safe design of transit structures. The focus was developing methodologies that engineers can use to calculate realistic derailment impact loading for use in bridge design. This report includes the conduct of research and findings used to produce the report, which is organized into seven chapters. The first two chapters include the background and literature review, introduction to case studies, and research approach. The middle three chapters include derailment simulations on a rigid deck and impact analyses on simplified and detailed bridge decks. The final two chapters discuss the development and validation of impact loading methodology, summarize the research findings, and provide recommendations for future research.

In addition to TCRP Research Report 257, a technical memorandum can be found on the National Academies Press website (nap.nationalacademies.org) by searching for TCRP Research Report 257: Determination of Actual Derailment Loads on Transit Bridges.

CONTENTS

Summary

Chapter 1 Background and Literature Review

1.1 Applicable Codes and Standards

1.2 Technical Literature on Derailment Simulations on Bridges

1.3 Train Derailments in the United States

1.4 Current Design Practices in LRT Bridge Construction

1.5 Existing Gaps in Research

Chapter 2 Research Approach

2.1 Modeling Approach

2.2 Modeling Considerations

Chapter 3 Derailment Simulations on Rigid Deck

3.1 Approach and Methodology

3.2 Results and Discussion

Chapter 4 Impact Analysis on Simplified Bridge Deck

4.1 Approach and Methodology

4.2 Results and Discussion

Chapter 5 Impact Analysis on Detailed Bridge Deck

5.1 Approach and Methodology

5.2 Results

5.3 Discussion

Chapter 6 Development and Validation of Impact Loading Methodology

6.1 Static Vertical Impact Loading Methodology

6.2 Dynamic Vertical Loading Methodology

6.3 Validation of Vertical Impact Loading Methodologies

6.4 Results of Vertical Impact Methodology Validation Analyses

6.5 Vertical Load Factors

6.6 Horizontal Impact Methodology

6.7 Discussion

Chapter 7 Summary and Recommendations for Research

7.1 Bridge Derailment Simulation Findings

7.2 Suggested Revisions to Current Codes

7.3 Suggested Future Research

References

Appendix Technical Background of Impact Loading Methodologies