I think you are correct. I was told once by a railroad guy that the contact area on a railroad wheel is less than the size of a dime in total area. The rail is wide, and so is the wheel, but they are coned, so they only make contact at one point, and it's about as thick an area as a paperclip, straightened and layed out flat.
That’s true and part of the reason conventional locomotives can’t negotiate steep inclines