When I learned to ski at Tyrol Basin in the mid-'60s, they had an old Oliver crawler with 2x4's added to the tracks for grooming.
My neighbor Eric drove it. There was no place to put his feet, and with the tracks right down below it was sort of scary just to drive. There was one pretty steep run, and Eric says when he got the cat sideways it would just take off to the bottom of the hill.