power controller for model railways

Since the day that Stephenson began taking an interest in coal, "model railways" has grown into one of the most popular of hobbies: the creation of a world in miniature that lives and breathes on railway lines. The illusion can be woefully shattered, however, when an engine is actually put in motion. All too often the locomotive takes off like a startled rabbit, much to the consternation of the mini-passengers. If this were to happen in real life, time-tables would become irrelevant. Our power controller shows that it can be different. power controller for model railways A power controller is, of course, intended to regulate the speed and direction of a model train. Ideally, it should give continuously variable control from a mere crawl to full speed. Before transistorized circuits became com- monplace, controllers were of two types: the rheostat or variable resistor and the variable transformer. The rheostat, con- nected in series with the locomotive motor, provides some control ...