The National Academies

NCRRP 02-01 [Completed]

Comparison of Passenger Rail Energy Consumption with Competing Modes

  Project Data
Funds: $400,000
Research Agency: TranSys Research, Ltd.
Principal Investigator: Gordon English
Effective Date: 5/17/2013
Completion Date: 12/1/2015


Lower fuel and energy consumption as well as lower greenhouse gas (GHG) emissions per passenger trip are frequently cited benefits of passenger rail in comparison with other, competing travel modes. Yet these benefits are not well documented nor are procedures for measuring them well delineated. Many currently available analyses of energy and GHG emissions reduction impacts of passenger rail service have significant shortcomings:
  • Passenger rail fuel consumption data may not fully represent impacts, since they are based on broad averages that include many different variations in distance traveled, amenities provided, speeds, operating environment, type of train operated, and form of propulsion. Similarly, energy consumption estimates for competing modes usually represent broad averages that do not necessarily reflect the energy profiles of comparable trips on modes that compete with passenger rail service accurately.
  • Using disaggregated data, linked more directly to where and how the fuel and energy attributable to specific trips is consumed, can provide a greater understanding of what is actually occurring. In addition, significant variations in fuel and energy consumption can occur by regions of the country and by individual states and metropolitan areas, and these variations should also be taken into account when analyzing comparable modes of travel, along with specific characteristics of available technologies and operating environments.
  • The pace at which new energy technologies may be put into service differs markedly between passenger rail and competing modes. To date, in the passenger rail industry, decisions about train types and operating patterns have not been strongly influenced by energy use and efficiency concerns. Instead, many technology and operations decisions have been motivated primarily by safety concerns, the ability to use proven equipment designs, initial implementation costs, and the need to work within existing operating and infrastructure constraints. In contrast, competing modes may be moving more aggressively to reduce energy consumption.
There is a need for research to (1) compare fuel and energy consumption between representative door-to-door rail trips and comparable trips by competing travel modes and (2) provide guidance for potential energy savings in the future.


The objective of this research was to provide like-for-like comparisons of energy consumption and greenhouse gas emissions for commuter and intercity passenger rail operations and for competing travel modes. To accomplish this objective, the research included the following::
  • An analytical framework for equivalent comparison of mode-to-mode fuel and energy consumption and GHG emissions, applied to case studies using disaggregated data (scope 1 and scope 2 emissions only, as defined by The Climate Registry);
  • A quantitative decision-support tool for evaluating and comparing fuel and energy consumption and GHG emissions by commuter and intercity passenger rail operations and by competing modes of transportation for comparable trips; and
  • An evaluation of opportunities to improve fuel and energy efficiency and reduce GHG emissions for intercity and commuter passenger rail.
In the context of this research, “passenger rail” includes higher speed, high speed, intercity, and commuter rail—those systems that are operated under the jurisdiction of the Federal Railroad Administration (FRA). Competing modes of transport include passenger automobiles, light-duty trucks often used for personal transportation, suburban commuter bus services, intercity bus services, and air transportation. An international perspective should also be addressed as appropriate.


The purpose of this research was to provide passenger rail stakeholders and policymakers with better information on passenger rail energy consumption and to help guide future actions to improve understanding and measurement of passenger rail energy consumption in comparison with that of other modes. The collected data and the decision-support tool, a desired product of this research,  includes sufficient documentation of analytical assumptions, including those concerning technologies and technology performance. The research product also provides mode-to-mode comparisons applicable to specific corridors and regions around the U.S. and a framework and tools for future comparisons.

With that guiding principle in mind, the research plan included the following:
  1. A targeted literature review coupled with industry outreach addressing fuel and energy efficiency and GHG emissions for passenger rail and competing modes for comparable trips.
    1. Review the domestic and international literature and data sources on transportation energy efficiency and GHG emissions for passenger rail and competing modes, and summarize the current state of the art.
    2. Identify and review opportunities for improvements in passenger rail fuel and energy efficiency, including both technological and operational changes that have had or may have an influence on fuel and energy efficiency. Impediments to fuel and energy efficiency improvements should also be identified.
    3. Identify trends in fuel and energy efficiency technologies and practices in competing travel modes.
  2. An identification of the set of parameters defining comparability for competing modes.
    1. Develop a method for direct comparisons between modes, which should include commuter trips, short-distance intercity trips, and long-distance journeys.
    2. Use a case study approach to illustrate application of direct comparison method(s).
      Note: To ensure like-for-like comparisons, the case-study section should draw from real-life trips, where trip lengths for functionally comparable trips (e.g., long-distance trips, trips to work, and intercity trips) are often dissimilar. Case studies, therefore, should be widely drawn from different parts of the country (urban, suburban, or other) such that trips between and inside of broad settlement typologies are covered.
  3. Calculation of fuel and energy consumption and efficiency, as well as GHG emissions for passenger rail service and competing modes for comparable trips.
    1. Develop a methodology for comparing modes, including, but not limited to, estimates of rail and competing mode fuel and energy consumption and GHG emissions, by passenger-mile and/or seat-mile. The methodology should also determine the breakdown of where energy is consumed by major function (e.g., propulsion vs. hotel power) for specific vehicle types and configurations.
    2. The breakdown should include fuel and energy consumption and GHG emissions as it relates to specific activities and other factors affecting usage rates (e.g., winter or summer HVAC, vehicle speed, exhaust treatment). Selection of vehicle type and configuration for this study should represent current and emerging trends in fleet composition among passenger rail operators in the U.S. All assumptions should be clearly identified.
    3. The calculations should consider and incorporate where appropriate the effects of changing congestion and operating environment characteristics on rates of fuel and energy consumption and GHG emissions.
  4. Development of strategies to improve rail fuel and energy efficiency and decrease GHG emissions.
    1. Identify and evaluate energy-saving opportunities for passenger rail.
    2. Include comparisons between diesel-fueled and electric-powered trains, locomotive-powered, and multiple unit trains, as well as emerging technologies and operating methods, and quantify expected changes.
    3. Identify and address barriers to innovation in the passenger rail industry, such as cost, perceived reliability risks in new technology, and existing investments tied to existing technologies.
  5. Development, application, and validation of a decision-support tool for evaluating fuel and energy consumption and GHG emissions by commuter and intercity passenger rail operations and by competing modes of transportation for comparable trips.
    1. The tool should be adaptable to address current and future technologies that can improve the fuel and energy efficiency and GHG emissions of passenger rail operations.
    2. It should be useable by various rail industry stakeholders.
    3. It should be based on an open-source platform, and it should be applicable to varied transportation corridors.
    4. The final product should provide end users with the ability to disaggregate data (to view energy usage data and drivers behind rates) and to compose calculations of aggregated energy consumption and GHG emission production for each service with assumptions clearly identified.
The final deliverables include a final report, documenting the entire research effort, and other deliverables as described in the research plan. Deliverablesalso include an executive summary that can be used to present key issues and conclusions to critical stakeholders.

To create a link to this page, use this URL: http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=3482