It's a simple concept, but it can be really tricky. It's fun and I can see it being taken further (looking at the buildings along the way). I like that I could stand in place with the rail to let the train drive over me. Those were fun moments.
I found the placement to be tricky. In order to place a rail, I needed to face a certain direction, but I needed 2 spaces to turn around and face the right direction. This really increased the challenge and the number of steps I took to solve the puzzle.
I eventually had a round without a cart. I think the levels may be randomized at that point.