Okay kiddo, so you know how trains have those big round things that they roll on? Those are called wheels.
Now, a wheelset on a train is actually a set of two wheels that are connected to each other by a piece of metal called an axle. The axle is like a long stick that goes through the middle of the wheels and holds them in place.
These wheelsets are super important because they help the train move along the tracks. As the wheels turn, they create friction with the track which propels the train forward.
But, it's not just about moving forward. The wheels also help the train stay on the track and go around turns. They have to be specifically designed and maintained to work with the shape and size of the tracks.
So, that's a wheelset on a train in a nutshell. It's a set of two wheels connected by an axle that help the train move forward and stay on the tracks!