I read some papers in the field of rail-wheel lubrication. Most of the cases they were limited to numerical models. I am thinking about using SPH solid modeling in rail-wheel contact. I am not sure SPH can be used in this way.
I saw the simulation of water splashing due to a car tiers with SPH and may be this problem like yours. I don't have the article of the water and tiers but if I obtain that I'll send it to you.