What went on int he engine house....

The Uintah Railway's engine facilities accomplished alot of thing over the years of 1904-1939, and I'm hoping that you guys can help flesh out what went on where in the facilites there. The main engine house was wooden structure, aproximately 200' feet long and had two parallel tracks running the length of the building with doors at only one end. These wo tracks had cement pits betwwen the rails and a small "alley way" between the two pits for locomotive maintenance. Perpindicular to this long building was a cement walled building that was the "machine shop". The two buildings were attached, with access between the two. The machine shop has a single set of tracks that ran in to the building from the east side ( parrallele with the roof line). Teh machine shop had every manner of equipment in it and that equipment ran off of a belt and pully system, hung from the ceiling, and powered with a stationary steam engine.
I have never seen a photo of the doors to the machine shop open, with an engine setting in that location.
What reason would there have been to run a locomotive in to the machine shop? In reboilering a locomotive, or builing one up from scratch, what would the closer proximity to the shop machinery provide in the form of efficiency. I have often wondered why there was a door on the machine shop, with a track going into it, as it would seem a locomotive setting on the floor of the machine shop would be "in the way". But then I really know very litle about rebuilding a locomotive, and am hoping some of those on this board with some expertise might have an idea as to why the building was built hat way in the first place. ALso would the machine shop, or the adjacent engine house, be a better place for a hoist for larger heavy items.
Thanks.