Steam motor

Okay kiddo, have you ever seen a train running? Do you know how it runs? If it uses coal to make steam and move, then it has a steam engine to pull the train.

So you know what steam is right? It's like a gas that comes from boiling water. Steam engines are like special machines that use that steam to make something move.

Just like when you blow up a balloon by blowing air into it using your mouth, steam engines make things move by using steam, which pushes something called pistons back and forth. And when those pistons move, they help turn a big wheel, which finally moves the train.

I hope that makes sense, little one!