We just learned about the Locomotion No. 1.
Another part of how steam locomotives work is the Fire-Tube Boiler.
A boiler is a big tank of water that is heated up to where the water boils and turns to steam.
There are a lot of different kinds of boilers, and the one called a fire-tube boiler was the one most used by steam locomotives to run the engine.
It's called a fire-tube boiler because there are a bunch of metal tubes that take in heat from a fire and then the heated up tubes make the water hot.
The hot water then turns to steam that is used with a steam pump to drive the gears that turn the wheels of the train.
![Fire-Tube Boiler](https://upload.wikimedia.org/wikipedia/commons/0/09/Locomotive_fire_tube_boiler_schematic.png)
![Fire-Tube Boiler](https://upload.wikimedia.org/wikipedia/commons/thumb/b/be/Aufgeschnittener_Kessel.jpg/640px-Aufgeschnittener_Kessel.jpg)
(from: wikipedia - fire-tube boiler)
Kid Facts - Blast from the past: Motor