Excuse me if I'm out of touch a little bit since I've been in Germany now for a few years, but are you talking about the "Snail Bus" from the D&S? If so then it must be surely the same now at White Pass. They alwas wanted to sell it at Durango after the end of the "Animas River Valley Railroad". It was a funny looking thing that was built at the D&S sometime in the early 90's. I hated it as a green fireman 1990 on the 7:30 train we had to meet it at "Needleton Siding" and if we (eer I) had problems we were late for the meet and then the Snail Bus was late for all the other 3 meets and the Boss always knew who had problems keeping steam up...
Later working in the roundhouse I found that the drive was orginaly an industrial Plymouth diesel switcher that was built into a new car body as a powertruck unit, the old mechanical drive didn't hold up to service so the "Rocket Scientist" converted it to hydrailic drive using Swiss hydralic 2 speed motors. The thing was permanently set in low speed as at high speed circuit it would have been capable of 45mph! There was thoughts of making a commuter service in the Hermosa Valley. There was never a shortage of good ideas at the D&S just a somewhat confused management.
Interesting side note that the open car matching to the snail bus was the smoothest riding car on the lot, but because the roof line didn't match the other cars a prior owner wouldn't let it run on normal trains. A condition the new owners seemed to have remedied.
Happy Trails
colorado narrow gauger in exile
Thor