The Great American Train Show is an event where people who love trains can gather together to look at different kinds of trains and things related to them. There are big trains you can climb inside and small trains you can watch go around tracks. You might see model trains that someone built with tiny little details to make them look real or real trains that are used for transportation. There might be people selling things like toy trains, books about trains, or t-shirts with train pictures on them. It's like a big party for people who love trains!