Usually electricity.
Lots, because a train is heavy. A 500 gallon fuel tank is small. BUT ... the amount of fuel used to move a ton of freight is roughly one quarter what it takes to move it by truck (and a tenth of what it takes to fly it).
fossil fuel is used in vehicles for transportation.
Nope - a train is a mechanical device.
The modern train runs on diesel fuel.
MAGNETS!
They don't actually have fuel, they have magnets. The track has powered electromagnets in it. The electromagnets make the train "hover" and propel it.
The fuel tank on a locomotive is under the locomotive body, between the trucks.
Coal or wood
To move the same weight the same distance by train uses less energy/fuel than if moving it with a bus.
Coal was burnt in the furnace. This heated water in the boiler to high temperatures. The steam was used to operate the pistons and to drive the train.
The only time a train has been powered by fish during coal shortage in Turkestan in 1919. Dried fish caught in the Aral sea were use as fuel . A total of almost 9000 tonnes were used to stoke the train's boiler.