Abstract: Placed near the transition point between power sources of different voltages or frequencies, is a wayside signal producing device which activates an on-board circuit for disconnecting the on-coming vehicle from the power source. When the vehicle has crossed the transition point, another signal producing device causes the vehicle to be connected to the other power source so as to resume power application. When the vehicle is proceeding in the opposite direction the sequence is reversed. In this way a multicar train can have the power source reliably switched in a car-by-car sequence without any appreciable loss in train speed.

Abstract: After vacuum pressure impregnating an insulated coil with liquid polyester resin the outer surface of the combination is treated to cause a quick low temperature gellation of an outer shell of the resin to thereby encapsulate the remaining liquid portion. A subsequent high temperature cure is imposed for a relatively long period of time to solidify the liquid inner portion and to fully cure the resin throughout the insulation.