The "Chama turn" ran as a three section train most times with two engines, bring cars to Cumbres and return to Chama. On the second day, they would depart Chama again for the final assault on Cumbres Pass. Arrive at Cumbres, put the train together as one, and let the helper run lite ahead of the freight. This was done to make sure the track was clear, and also lite engine was a lower rate of pay.
Power has to be distributed because heavy trains can rip apart very easily, or string line on tight curves. By rip apart, I mean the draw bars would come right out of the car. String line is a term when to much weight is going around a curve and the cars tip over towards the inside. By distributing power, it is like running shorter trains just with less crew members.