How does a steam locomotive work?

Here is a nice short video, apparently translated into English, that explains "How does a Locomotive Steam Engine Work?"

It shows a hot fire in a firebox, which can be fueled by wood, coal, or oil. That heats a boiler by piping the hot gases and smoke though water. That heats water to its boiling point, turning it into steam, and collects the steam which is piped back through the boiler and superheated under pressure. The very hot steam goes through a pipe and through valves which direct the steam alternately to one side of a cylinder and then the other to push a piston in the cylinder back and forth. The back and forth motion of the piston is converted into rotation of the wheels with the motion of a piston rod.