Locomotive Engine Running and Management

by Angus Sinclair

CALCULATING POWER OF LOCOMOTIVES.

The capacity of engines is generally expressed in horse-power, which is a measurable quantity; but, for several reasons, that method of indicating power has not been usually applied to the locomotive. When practical railroad men hear the size of cylinders, the diameter of driving-wheels, and the boiler dimensions of a locomotive, mentioned, they understand what kind of service the engine is adapted for, and about the weight of train it can haul. As it has been found necessary for designing and other purposes, to estimate, with some degree of accuracy, the work a locomotive is capable of doing, it has become usual to reckon the power of a locomotive by the tractive force it can exert upon the rails.