#20's last runs were in late November, 1951 when #20 hauled a string of empty D&RGW cars south from the soon to be isolated Ouray Branch from Rico to Durango. 452 went along as helper when needed. #20 had run as a caboose hop in from Durango the previous day, while #461 and #452 brought the empty cars from Ridgway. While #20 and 452 were working their way south, 461 cleaned out the Rico yard and moved the last few cars of revenue freight from the Rico mines over the hills and back to Ridgway.
This was the last use of both #20 and #452.
There were a couple of trips made out of Durango to Dolores in late December, 1951. These were powered by D&RGW #464, and were the last runs of the RGS before abandonment.