The Franklin Institute is building, in its Locomotive Room, a model railroad layout that wil1 be as realistic in scenic beauty and performance as one could ever desire. As a locomotive winds its way about the several loops, it maintains a constant speed regardless of the number of cars it pulls or the steepness of the grades it climbs and descends. The unit that automatically controls the speed of the locomotive is a unique feature of this "dream layout."
The problem of keeping a slow freight moving on an upgrade without stalling presents a nice challenge to anyone who desires a completely automatie layout.
Mr. Lynn H. Wescott, Editorial Directer of The Model Radroader Magazine, submitted a theoretic electronic circuit which, after further development, solved this problem very nicely and easily. With this control, the operator sets a throttle, throws a switch to start the locomotive, and then just sits back and watches it accelerate realistically to the pre-selected speed. As a grade is approached, the voltage supplied to the track is automatically adjusted to compensate for the change in load so that the speed remains constant.
Likewise, when the stop switch is thrown, the locomotive slows down to a full stop and power is automatically cut off from the track. An overload-detecting circuit limits the power-pack output to a safe value and, when the trouble is cleared, the locomotive speeds up to the pre-selected speed at which it was running before the overload occurred.
Trackside black signals can be connected into the electronic unit to start, slow or stop a locomotive automatically and thus make possible a completely programmed operation.