As noted above, when the RR was busy, trains ran 24/7 as needed. When possible they ran the freights as not get in the way of the passenger trains.
When the Alamosa-Durango line was at its busiest, they would try to coordinate the trains so that when a train arrived in Chama from the east, a crew was on duty and ready to take it on toward Durango with minimal delay. The Farmington Branch Crew would be waiting at Carbon Jct. to take the train south when they rolled off the hill. They would do the same for the eastbound move. A common scenario was out of Alamosa mid day, into Chama that evening, overnight to Carbon Jct., down to Farmington that morning, back that afternoon or evening, over the road to Chama that night. There would be multiple hill turns that next day to get the train up the hill, then a run through to Alamosa that evening, getting into Alamosa in the wee hours of the morning.
The guys who worked in Durango say they always seemed to work at night, "By the light of the Rio Grande Sun...."
Trains out of Salida to Gunnison were frequently nocturnal. There are stories that Bob Richardson told of hearing an eastbound coal drag was headed out of Gunnison. They'd work their way up the nasty road/trail to the summit of Marshall Pass in the afternoon, and sit up there all day looking down the valley for smoke, finally giving up at dark and going home. Later they found out the train didn't make up there until mid-night.
When the Monarch Branch was real busy, they ran two trains a day there - one during daylight, and another at night.
All-daylight operations out of Alamosa really didn't come along until the early 1960's when traffic slowed down, and no one was in a big hurry to get trains over the road.