What are the main sources of traction power in railway transport?

The main sources of traction power in railway transport are electricity supplied through overhead lines or third rails and, in some cases, diesel engines driving generators or directly powering traction motors. Electrified railways typically receive power from national grids, which may include renewable energy sources like wind or solar. The electricity is transformed and distributed along the railway network to power electric locomotives and multiple units. Diesel-electric locomotives generate electricity onboard using diesel engines. Emerging technologies also explore hydrogen fuel cells and battery-powered trains as alternative traction power sources, aiming to reduce emissions and dependence on fossil fuels.