Multi-scale evaluation of diesel commuter rail fuel use, emissions, and eco-driving

Abstract

• Diesel commuter rail fuel use and emission rates (FUERs) are quantified. • Key sources of variability in diesel commuter rail FUERs are quantified. • Diesel commuter rail FUERs are 7 to 8 times greater for hotspots than non-hotspots. • Eco-driving can reduce system-wide diesel commuter rail FUERs by 10% annually. • Mesoscopic eco-driving can mitigate or worsen FUERs hotspots. Diesel commuter rail emissions affect populations near rail corridors. An approach is demonstrated to quantify mesoscale and microscale diesel commuter rail fuel use and emission rates (FUERs) of CO 2 , CO, NO x , particulate matter , and total hydrocarbons based on two U.S. systems. A speed trajectory simulator, an energy model, and an emissions model were calibrated, evaluated, and applied. FUERs and potential reductions from eco-driving were quantified based on simulated trajectories. Hotspots were defined as sections with ≥ 90 th percentile of section-average FUERs by species. A few key variables explain 74–80% of variability in mesoscopic and microscopic FUERs. On average, FUERs are 7–8 times greater for hotspots than non-hotspots. Eco-driving was estimated to reduce segment-average FUERs by 3–33% and eliminate 2–11% hotspots. However, mesoscale oriented eco-driving can, at some locations, increase microscopic FUERs. The approach is adaptable to other diesel commuter rail systems.