From what I've read, it would seem roundhouses / enginehouses generally didn't do much of anything at night at least as far as repair work and such. There would on many railroads be situations where a train would need to change engines at a division point at 3 a.m. so there would have to be someone in the roundhouse to prepare the new engine and get the one coming off into a stall etc. of course.
Keep in mind too in the 1890's the 8-hour work day was a long way off in the future. I suspect railroad shop employees probably worked a 10 or 12 hour day.
SpaceMousefwright Also of note, major plants built before 1940s were full of windows. Working around the clock with electric illumination really didn't start until World War II. So you're saying, I probably shouldn't put lights in the engine house.
Actually it would be possible to have electric lighting in an engine house in the 1890's.
Edision started promoting installations using incandesent lamps in the early 1880's. Among the first industrial use was in mines but soon spread to other industries.
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.