Amusement Park Train Wear

Fellow NGDFers, in all the amusement parks I've ever been to, the train rides always seem to be in a circle. So here are my questions:
1. Does this make one side of the wheels wear out faster than the other side?
2. Does this put unusual strain on a particular side of all the drive rods, linkage, etc.
3. Does the constant starting and stopping do more damage to the cylinders rather than having a long haul of non-stop work of power being applied.
I always ask the crews that run these little trains and they usually tell me that they either run a different loco (if available) every other day or turn the train and go the reverse direction.
Thoughts anyone? " />
Tim