It's More Than Horsepower
Model Railroader 1978-11
The author describes how he created a "tonnage chart" where a certain number of engines are needed to pull a certain number of cars. The quantity and type of engines used in the consists are based on scaled-down prototype engines' performance numbers. He then bases the information on what kind of terrain the engines would be battling. It is an interesting way of adding to the realism of model railroad operations.