In the late 1940's before the wholesale retirement of the D&RGW's standard gague steam fleet, the La Veta Pass line tended to get lots of second-rate power. The Valley Locals would be powered by C48 2-8-0's and the trains over La Veta got compound 2-8-8-2 for power. When the D&SL was absorbed into the D&RGW all thier power came with the deal. By and large, the D&SL power was small and outdated. Thier 2-6-6-0's were too small for the Moffat and Tennesee Pass lines, so they were set aside rather quickly. 3375 was sent to Alamosa to run out it's time.
Eldon Morgan once told me he fired just about every SG engine class that came to Alamosa. I asked him about the D&SL Mallets amd he said "yes, they had 1 or 2 down here. I remember firing them. They were really worn out and didn't steam well. They were kind of cute though.. Once they needed the needed major work, they were sent off to scrap."
The boilers of 2 D&SL Mallets ended up in the Oriental Refinery in Alamosa.