if you turn 180 then it would be the left rail surely? On the other set of track that is
No
Um, if you turn 180 and examine the other right rail, is it also the most worn?
Yes.
In north hemisphere, when you move in any direction (exept exactly from E to W or W to E) the Coriolis effect produce a force to the right.
In fact, Coriolis effect is very easy to understand (if not, it's probably an effect of my bad english):
When you move from South to North, you become closer to the axis of rotation of the Earth (on the equator, you are at 6350 km of the axis; at 45° of north latitude, you are at 4500 km of the axis). As you are spinning with the Earth from West to East, like a skatter squeezing up his arms, the conservation of kinetic momentum make you accelerate in the direction of your rotating movement, so to the East (so to the right of your movement from S to N).
When you go from N to S, you move away from the axis of the Earth, so you deccelerate, so you are subject to a force to the West, so to the right of your movement.
I suppose you know that it is for the same reasons than the teeter axis of our rotors is a few centimeters above the plan of rotation of the rotorhead, avoiding this way the need of a trainee axis on the base of the pales (sorry, I'm not sure to use the right words in english).