In the early 1960's when I began visiting the Rio Grande narrow gauge, trains between Alamosa and Durango (and the Farmington branch) typical ran about twice a week. However two times a week meant six days of operations, since getting from Alamosa to Durango took two days, and a third day to make a round trip from Durango to Farmington. Trains would typically leave Alamosa and Durango on the same day, meeting at Chama.
Between Alamosa and Cumbres virtually all trains had two engines. They would doublehead from Alamosa to Antonito. At Antonito they would top off coal and water, cut the helper into the train and head for Cumbres.
It was a long slow trip and trains rarely arrived Cumbres before dark. At Cumbres the helper would be cut out and run light down the hill to Chama. The road engine would follow with the train.