Back when the Gramps field was a going concern, it could be counted on for 10-12 cars a day. That would be one full tonnage (for two engines) hill turn every day. It was the oil traffic out of Chama that kept the RR running 12 months of the year. When the refinery closed and the oil stopped moving the rest of the winter time traffic could be diverted to Rio Grande Motorway trucks, and they started shutting down in the winter.
So, I imagine there were quite a few solid oil trains up the hill, if all 12 were loaded and ready at the same time. Otherwise they got stuck into other hill turns a few at a time. The program was to get all the loaded cars up the hill first (oil and lumber, mostly with a little coal), then fill the train out to 70 cars total with empties and head for Alamosa. depending on the timing there could be more thatn 11 cars of oil going east. Coming west the empty tanks were just another empty car in the train.