As long as you align the textures on the plane, it'll at least look passable
The train seems really really narrow. There could be alternate paths, but wouldn't it be
1) The top of the train, for high-jumpers
2) The left side of a car
3) The right side of a car
I can't think of any others, and splitting such a narrow path again (left and right) would make it ridiculously narrow.
A suggestion, is to make the cars larger than life - TF2 has a cartoony theme, and extra-big cars would fit in decently if they're done right. You could then build in multiple levels / sidepaths that don't feel too constricting.