D&RGW used it for a few years. We have movies of this train, as it was on the point of #7(really 476) on the Rocky Mountain Railroad Club trip in 1954. I have the details of the info on it in the video, which will release in Oct/Nov. Just got the DVD's in a week or so ago, so they will be ready. Dad has some nice shots of it from the cupola which was behind the engines. They did a runby without the diesel at the High Line, then put the diesel back on the point after the Animas River Bridge. At Silverton there is a shot of the diesel coming off as the train was facing south before the return trip. Diesel went back light ahead of the train.
The excursion started from Alamosa the previous day with 487, which also pulled them back to Alamosa with help from 492 out of Chama to Cumbres. I can't recall the specifics without looking at the video, but it was later scrapped. I do remember it was built for the Army and had reguagable trucks for 3 foot 6" as well.
Greg Scholl