Rail Real-World Emission Measurements and Models

Measurement and Modeling of Locomotive and Train Energy Use and Emissions

This research pioneered the use of portable emissions measurement systems (PEMS) to characterize the real-world fuel use and emissions of diesel passenger locomotives and trains. The work provided first-of-its-kind data on locomotive emissions under various operating conditions, including dynamometer tests versus rail yard operations and the effects of biofuels. More recently, this research has led to the development of methods to identify “emissions hotspots” and evaluate the energy-saving potential of “eco-driving” strategies for passenger rail systems, providing a scientific basis for operational and technological improvements in the rail sector.

Illustrative papers (selected examples): 

Development of Methods for Measuring Locomotives Using Portable Emission Measurement Systems

Frey, H.C., H.W. Choi, and K. Kim, “Portable Emissions Measurement System for Emissions of Passenger Rail Locomotives,” Transportation Research Record, 2289:56-63 (2012).  DOI:  10.3141/2289-08.

Graver, B.M., and H.C. Frey, “Comparison of Locomotive Emissions Measured during Dynamometer versus Rail Yard Engine Load Tests,” Transportation Research Record, 2341:23-33 (2013).

Graver, B.M., and H.C. Frey, “Comparison of Over-the-Rail and Rail Yard Measurements of Diesel Locomotives,” Environmental Science and Technology, 49(21):13031-13039 (2015), DOI: 10.1021/acs.est.5b02497.

Measurement-Based Assessments of Passenger Rail Emissions

Graver, B.M., and H.C. Frey, “Highway Vehicle Emissions Avoided by Diesel Passenger Rail Service Based on Real-World Data,” Urban Rail Transit, 2(3-4):153-171 (2016).

Graver, B.M., H.C. Frey, and J. Hu, “Effect of Biofuels on Real-World Emissions of Passenger Locomotives,” Environmental Science and Technology, 50(21):12030-12039 (2016), DOI:  10.1021/acs.est.6b03567, October 3, 2016.

Rastogi, N., and H.C. Frey, “Characterizing Fuel Use and Emissions Hotspots for a Diesel-operated Passenger Rail Service,” Environmental Science & Technology, 55(15), 10633-10644 (2021). https://doi.org/10.1021/acs.est.1c00273

Rastogi, N, H.C. Frey, and T. Wei, “Identifying emissions hotspots and strategies to reduce real-world fuel use and emissions for passenger rail: A spatially resolved approach,” Science of the Total Environment, Volume 896, 165110, October 2023.

Modeling of Train Operations, Energy Use, and Emissions

Yuan, W., H.C. Frey, and N. Rastogi, “Quantification of Energy Saving Potential for a Passenger Train based on Inter-run Variability in Speed Trajectories,” Transportation Research Record, Vol. 2673(5):153–165 (2019).

Yuan, W., and H.C. Frey, “Potential for Metro Rail Energy Saving and Emissions Reduction via Eco-driving,” Applied Energy, 268, article 114944, 13 pages.  June 15, 2020.  https://doi.org/10.1016/j.apenergy.2020.114944

Yuan, W., and H.C. Frey, “Multi-scale evaluation of diesel commuter rail fuel use, emissions, and eco-driving,” Transportation Research Part D: Transport and Environment, Volume 99, October 2021, 102995. https://doi.org/10.1016/j.trd.2021.102995

Ahn, Kyoungho, Ahmed Aredah, Hesham A. Rakha, Tongchuan Wei, and H. Christopher Frey. 2023. “Simple Diesel Train Fuel Consumption Model for Real-Time Train Applications” Energies 16, no. 8: 3555.