Boiler

Boilers are large cylindrical water tanks found on steam-powered vehicles . They have a cluster of heating tubes going through, connecting a firebox at the back with a smokebox at the front of the vehicle. Hot air and smoke from the firebox go through these tubes, heating up the water inside the boiler, eventually causing it to evaporate. Since steam is compressible, so much of it can be generated in the limited volume of the boiler, that it becomes highly pressurized.

Most steam engines have a safety valve that will release excess steam in case the boiler is overpressurized. It is advised to have just as much pressure in the boiler as needed to operate the engine, and not more, as the excess leads to wasting fuel .

Water is fed to the boiler from storage using an injector . Since stored water is cold, adding it to the boiler can condense steam back into water, resulting in pressure drop, so it needs to be done carefully.

The boiling point temperature of water depends on the amount of pressure in the boiler. The higher the pressure, the higher the boiling point.