There are photos of this same train in the John W. Barriger III collection in the St. Louis Library.
www.flickr.com/photos/barrigerlibrary/albums/72157640595666535/with/12348783474/
In this collection there are three sets of photos, one with engine 40 and the B-20 that covers virtually the entire line, and has some very interesting photos of the Durango end.
The second set is #25, and appears to be the train in these photos as well, and it was run from Ridgway to Dolores and back.
The third set is a goose excursion after WW2.
In the the 1930's Barriger was with the Reconstruction Finance Corp and was evaluating railroads for Federal aid during the depression, and I would guess that the first two trips were precisely for evaluating the RGS .
Here are a few photos of the second trip with what appears to be the same consist as the photos above.