We just learned about the Trailing Wheel.
Another part of a steam locomotive is the Brake Shoe.
When the train has to stop, there is a rounded piece of metal called the brake shoe that is pushed against the wheels to try and slow them down.
The scraping of the brake shoes on the metal wheel also helps clean the wheels, and after a while the brake shoes get worn down and need to be replaced with new ones.
(from: wikipedia - brake shoe)
Kid Facts - Blast from the past: Electromagnet
