Dave,
Makes sense and thanks for the detailed explanation. I’d also imagine the angle of attack would also contribute to rail wear.
Model Railroader had an article on grades in issue from 1968, and the effect of curves on train resistance has intrigued me since. Specifically how much was due to the wheels slipping against each other and how much was drag from the forces pulling the wheels towards the center of the curve. Most of the texts on calculating train from years ago tend to punt on the “true cause”. Figure this is sort of the flip side of adhesion versus curvature.