Investigating dwelling of freight trains with a view to the reduction of carbon and pollutant emissions

Abstract

Many freight trains are still diesel-powered, and their CO₂ and other emissions cannot be ignored. This research proposed a framework to evaluate freight trains’ stops during their journeys and the associated emissions from idling and reacceleration. It includes (1) number of stops, (2) stopping time (duration) and (3) stopping percentage (a train’s total stopping time divided by its journey time). The framework was applied to integrated datasets of Great Britain from January to June 2022 to evaluate freight train operations and estimate emissions. We found that 83% of the observed 105,714 freight trains were diesel-powered. Each diesel freight train made an average of 1.34 stops during its journey, with an average total stopping time of 17.2 minutes and a stopping percentage of 6.89%. It was estimated that in that six-month period 53.12 ktonnes of CO₂, 0.35 ktonnes of NO_x and 6.58 tonnes of PM were emitted from diesel freight trains. Domestic Intermodal (containers) accounted for 60% of the emissions, followed by Construction (23%). Many emission hotspots were along lines with high-frequency passenger services. The developed framework could be used to evaluate railway timetables and operation management at a national level.