How does trains work?

Answer 1

A steam engine has a large boiler and a place under it where a fire burns. The boiler is basically a big tank with water. The firepit can have coal, wood, oil, or gas, depending on its design. Basically, the fire heats the water until it boils, and steam comes out a hole which has a pipe connected to it to funnel the steam into a chamber holding a piston.

The increased pressure in the chamber forces the piston back, uncovering a hole where the steam can escape. The piston is attached to a swivel point on a wheel. As the piston moves back and forth, the wheel turns because the piston is cranking the wheel via the swivel point.

The boiler needs to be refilled periodically as the escaping steam is water leaving the boiler. The fuel must also be replenished, or the fire will go out.