Hey, I happened to make a Train themed game too! Cheers.
The gameplay is very methodical and clunky, just like I imagine operating a real train car shunter would be. I think you could make things a bit more fun if you could move the shunter with the arrow keys, simply to free up your mouse for the couplings/rail switching. After figuring out the logic of a puzzle, it's still quite tedious to complete it.
I made it as far as the level with two train cars, I accidentally got some of my bottom cars stuck under the coal dispenser.
Thanks for sharing the game!