Okay, imagine a big, long train that runs on these little tracks called tramways. The Bathurst Decauville Tramway was one of these trains that ran in Australia a long time ago. It was used to carry lots of things like coal, timber, and food from one place to another.
Now, Decauville was just the name of the company that made the train, kind of like how your toys have a brand name. This train had a special design which made it really good at carrying heavy things up and down steep hills.
The Bathurst Decauville Tramway was actually really important because it helped people who lived in the area get their work done. Before the train, it was really hard to move really heavy things around, but with this train, it was so much easier!
Even though the train isn't used anymore, it's still remembered as an important part of history in Australia. People still go to see it and learn about how it helped the people who lived there a long time ago.