My train has issues staying on the tracks!

Hey guys,

I'm fairly new to Unity, and I decided to try and build a procedurally generated railroad game. I'm currently having an issue with the train I've built (it's a crummy train, but I needed something to work with in 5 minutes) where it has trouble navigating curved sections. It works fine on straight sections, but on curves, it's handling is very unpredictable. Here's the setup I've got going:



Each wheel has a WheelCollider on it, but for some reason, the geometry of the wheels aren't taken into account at all. Furthermore, half the wheels are flipped backwards. What am I missing here?