California Air Resources Board

Principal Investigator/Author: Georgios Karavalakis

Contractor: University of California, Riverside

Sub-contractors: Link Engineering Company, Eastern Research Group, University of California, Irvine, San Diego State University

Contract Number: 23RD010

Project Status: Active

Relevant CARB Programs: Mobile Source Emissions Research Program, Community Health, Reducing Rail Emissions in California

Topic Areas: Non-Exhaust Emissions

Research Summary:

California has 4,981 miles of freight rail tracks and ranks among the top three states in the nation for freight rail carloads.  To address emissions from locomotives and railyards, the California Air Resources Board (CARB) has developed and implemented several studies to better understand and reduce locomotive and railyard emissions.  A new In-Use Locomotive Regulation (Title 13, California Code of Regulations, sections 2478 through 2478.16) aims to reduce exhaust emissions, including harmful pollutants such as diesel particulate matter (PM), nitrogen oxides (NOx), toxic air contaminants, and greenhouse gas (GHG) from diesel-powered locomotives.  This regulation will promote the adoption of zero-emissions (ZE) technology.

However, there is limited information on the emissions of particles from train brake-wear and wheel/rail-wear (BWWW) and their potential health risks.  Researchers will address this gap by studying BWWW emissions and train activity patterns.  The research team will develop tools for data collection, measure BWWW emissions both on the rail and in laboratory settings, analyze data by train type to create emission profiles, and develop a model to better understand how these emissions affect air quality.  They will also estimate exposure levels and potential health risks for communities near railways, and recommendations and programs to protect these vulnerable areas.   

Project results will support several California initiatives, including 1) Reducing Rail Emissions in California; 2) Developing emission inventories for off-road non-exhaust emissions including locomotives and railways; and 3) Assessing the impact of particle emissions on communities near railways.  The results could also inform future CARB policy considerations. 

Keywords: particulate matter emissions, brake-wear, wheel/rail-wear, non-exhaust emissions, railway air quality, emissions reduction