Weight distribution on electric locomotives as affected by motor suspension and draw-bar pull

In a locomotive propelled by electric motors the motor action produces a set of stresses acting between the truck-frame, motor supports, and driving-wheels. The horizontal effort at the rail-head resulting from these stresses acts against the resisting forces of the locomotive, the principal items of which may be considered as: a. The rolling friction of the wheels on the track, acting at the rail-head. b. The resistance to acceleration due to inertia of the locomotive, and the resistance due to grades, acting at the center of gravity of the locomotive. c. The air resistance, acting at the exposed surface particularly at the head end. d. The resistance of the trailing load, acting at the draw-bar. The effect of the forces here discussed including the internal or driving forces acting between truck, motor, and wheels, and the external or resisting forces, produces a shifting or redistribution of the weight on the various wheels. In the following paper the attempt has been made to investigate the amount of this redistribution. The discussion is limited particularly to locomotives drawing trailing loads, since this redistribution of weight is particularly effective in the case of a locomotive exerting a horizontal effort at approximately the slipping point of the driving-wheels. Some of the general limitations and considerations applying to this particular case must be clearly defined.