Re: Triple headers versus double headers or breaking trains up

Multiple locomotives would be used in a train simply to provide sufficient horsepower to move the calculated weight of the train. When a steep grade was encountered, rather than add even more locomotives, the train would be "doubled" (and on the rare occasion, tripled) over the pass using the power already there.
Another example of multiple locomotives on a train is pictured on pp 19-22 of Kramer's "Twilight on the Narrow Gauge" (Quadrant Press Review #5) that shows train of cattle cars leaving Parlin bound for Salida with 2 locomotives on the head end. At Sargent 2 more locomotives are added mid-train in order that the train can surmount Marshall Pass without doubling, as the clock is running on cattle loaded on a train and too much time would be wasted doubling the hill. Hope this helps answer your question.