In the real world the total number of degrees of left curvature has to be very, very close to the total number of degrees of right curvature or the railroad would be running in circles. So locomotives and rolling stock have equal flange wear left and right sides. OTOH, rail does wear unequally on curves with the outside railhead wearing on it's inside side. For this reason railroads with lots of sharp curves periodically relay rail to equalize wear on curves. Also for this reason railroads install flange-oilers just before sharp curves.
With models it takes one heck-of-a-lot of running to cause wheel wear but it does happen. Worn model track? I haven't seen any.
