Page:Popular Science Monthly Volume 37.djvu/401

Rh locomotive may be seen in Fig. 3, under the motor. While ascending a steep grade the current will be on for almost the whole time; while descending such a grade it will be off altogether; on level stretches it may be on for, say, a quarter of the whole time of running. This plan avoids all waste in switches or interposed resistances, and the current cut off by each governor is too small to injure the dynamo.

But since a train when going down a steep incline is liable to get up too great a speed, even without its motor receiving any



electricity, the locomotive is provided also with a brake, shown in Fig. 5. This is placed on the shaft of the motor, and the edge of it may be seen in Fig. 3, beside the cog-wheel A. In Fig. 5, W W are two weights whose centrifugal force, up to a speed of eighteen hundred revolutions of the shaft A per minute, is balanced by the springs S S, but above that speed the weights draw outward and press the wooden brake-blocks B B against the metal ring C, which is fixed to the frame of the locomotive, thus retarding the motion of the train.

The method of working telpher trains employed at Glynde is what the inventors call the "Cross-over Parallel System." Fig. 6 is a diagram showing the electrical connections according to this system, where an up and a down track are used. Each track is divided into sections, each span of the ordinary length being a section. Alternate sections of each track, A1, B2, A3, B4, etc., are electrically connected together and to one pole of the generator of electricity D; the other sections are also connected together, and to the other pole of the generator. The two sets are well insulated from each other. Only two wheels of a train are employed