Roger:
That is a D&RG K-27 "Mudhen" on Marshall Pass, probably around 1911-12. It is probably 458. 458 was regularly used on the passenger train out of Salida over to Sargents where one of the T-12s would take it on to Gunnison and Montrose. I have a photo showing 268 double heading with 458 and I think it is the same location.
The mudhens orginally were compounds but were converted to simple within a few years. They kept the slope back tenders until 1919. Take a look at the RRobb book on Mudhens by Dennis O'Berry for more pics of them.