Damn, more research. The tax assessor's records will show when a building first appeared on the lots where the SN engine house sits. That may be a moot point as all railroad property (and all public utility property as well) in Colorado is assessed by the state, and not each individual county, but I don't know when that started. But. I have to go by the courthouse in the morning anyway, so I'll see what I can find.
As to the photo mentioned by John, that wood cross walk was replaced by concrete in 1912 when the town put in concrete sidewalks, and the cut they made in the concrete to allow for the tracks to pass through is there today--just have to know what you're looking at. As an editorial consultant to the Rainbow Route, I'm afraid that most of my comments and corrections were not used as type had been set and Del and Russ were not in a financial mood to go back and make corrections. The last chapter in particular has numerous errors in the text that I'm afraid will be used as the gospel by those doing research in the future who do not do their basic work.