I was looking for something else (substantiation of Brunk and Abbott of a stockyard and loading chute in Silver Plume) and I ended up stumbling on something entirely different, something I had never seen before = a contemporary (1878) cartographic depiction of the original CCRR Georgetown track layout, complete with enginehouse (located on the tail of the wye ?!?). The excerpt is from a map published five years before the GB&L began laying track in August of 1883.
When I redrew the original Georgetown Yard map, you could see imprints in the map of some of the tracks listed.
The Engine House has been a matter of speculation by a few modelers who said that the Wye was too tight to handle a locomotive and that the tail track was in the Engine House. I told them in reply that back then the largest power to Georgetown were 2-6-0's Somebody speculated that it was an "Engine House" for a mine. Why an Engine house would be located that far from the nearest mine is beyond me.
I guess that we just have to load up our cameras and hop in the time machine to settle it.
I, for one, believe that it was a Railroad Engine House and that it was built to keep those small locomotives out of the elements during the Colorado winters.