Jimmy
I would say that is Montrose, but before 1940. I say this as engine 20 still has it's old tender. This tender was replaced in 1940 with engine 25 tender, 25 been cut up.
The only thing that comes to mind is the D&RG is short power at Montrose and is using RGS 20 to go east to Gunnison on train 316.
Going into Colorado Rail Annual 1970 it shows that passenger service throught the Black Canon ended in 1936, so that puts this photo late 1920's early 1930,s It is a good photo are ther any more?
Bill.