Sorry, but I have to "jump" in on this question(no pun intended!). Most of the rails I have seen are either steel pipe, or flat channel pipe covered with plastic.
Ski bases and edges were NOT designed to slide on anything other than snow, even those skis specifically designed for rail sliding. Add to this the fact that most rail slides are done on the bias (with the ski sidewards to the direction of travel), and you can begin to imagine the damage that will be done to your bases. May as well take them out your first day, and wear them through the parking lot!
Maybe this is designed to encourage jibbers to buy skis more often, as I've seen some really chewed up gear come in off the hill/ out of the park. Blown edges, ripped bases, bent skis.
It would be pretty difficult to even imagine skiing on this wrecked gear, with any degree of control.
My suggestion- . Get on the For Sale section here, or ebay or where ever, and buy a pair of junkers you can go out and trash, with out feeling guilty for having ruined a perfectly good pair of skis!