Electric trains do not produce direct "tailpipe" emissions at the point of use, making them significantly cleaner for urban environments and local air quality compared to diesel or steam locomotives. However, their total environmental impact depends entirely on the source of the electricity used to power the overhead lines or third rail. If the power grid is supplied by coal or natural gas power plants, the pollution is essentially "displaced" from the tracks to the power station, where carbon dioxide, sulfur dioxide, and nitrogen oxides are released. In 2026, many European and Asian rail networks have shifted toward "Green Traction," sourcing 100% of their energy from wind, solar, and hydroelectric power, resulting in near-zero life-cycle emissions. Additionally, electric trains produce "non-exhaust emissions" such as particulate matter from brake wear and the friction between the wheels and the steel rails. Despite these factors, electric rail remains the most sustainable form of high-capacity motorized transport, as it is vastly more energy-efficient than air or road travel for moving large numbers of people over long distances.