In the late 1970's there was an overflow "second section" that ran during peak season from Cumbres to Sublette and return using the helper locomotive. There was a short string of cars left up at Cumbres for this. Caboose 05635 was built for this train. The train would depart Cumbres after the regular train and follow it to Osier. What I don't remember hearing was whether it stayed behind the train all the way to Sublette, or ran around the train at Osier. I don't recall when the west siding switch was re-installed, so that piece of information could answer that question. My guess is it followed behind the regular train.
The train went to Sublette, where the passengers were unloaded and the engine ran on to Big Horn to turn. When the engine got back to Sublette, they made their way home. This was a real low budget operation. The 05635 was probably the item requiring the most capitol outlay. The open gon was the car that came from the Lake Tahoe operation (still lettered T.T.C.& P.) There were 3-4 boxcars that were opened up on one side only, the canyon side.