Analysis of particulate matter emissions from rail traffic during train braking cycles with emphasis on particle size distribution, ultrafine particles and black carbon emissions

Abstract

Rail transport is generally considered eco-friendly compared to other transport methods. However, it still contributes to environmental impacts, particularly in relation to air

quality. Transport emissions can be classified into two categories: exhaust emissions from engine combustion processes and non-exhaust emissions, including brake wear,

wheel-rail abrasion, as well as particle resuspension. While environmental regulations have been well-established for exhaust emissions, non-exhaust emissions remain

relatively less explored. This research project focuses on measuring and analyzing non-exhaust particle emissions generated during train braking cycles, with a special

interest on ultrafine particles and black carbon, due to their potential health implications. To accomplish these research goals, this project encompasses a literature review

of non-exhaust-related emissions in train systems, a comprehensive data analysis from the brake test bench utilizing various measuring devices and under multiple

measuring programs following the DIN EN 16452:2019. Different operating conditions were evaluated such as the train mass, initial velocity, and contact force between the

wheels and braking pads to determine the most critical operating condition for the emission of particles, ultrafine particles and black carbon