Model Trains & Radio Control
Radio control (R/C) is not only possible, it is becoming a widely accepted means of controlling large-scale trains. Several manufacturers offer R/C gear designed specifically for use with trains. The way R/C works is relatively simple in theory. You must have a transmitter (Tx) to send the signals and a receiver (Rx) to receive them.
The transmitter is most often a hand-held device that can range in size from a pack of cigarettes to a small hard-bound book. Batteries are carried in the transmitter to give it power. These can be regular alkaline batteries or rechargeables, usually nicads (nickel-cadmium).
The receiver is usually (though not always) carried onboard the train. It requires batteries to run it as well. A second, much larger battery (or batteries) is required to run the motor(s) in the locomotive. Many modern-day R/C sets have a built-in battery-elimination circuit (BEC) that allows you to do away with the receiver's batteries. The receiver will then run off the same batteries that power the engine.
The receiver translates commands from the transmitter to a circuit through with power to the motor travels. This circuit controls the polarity of the electricity -- and hence the direction of travel -- and the amount of power delivered to the motor, or the speed of the engine.
Large locomotives may have enough room onboard to carry both batteries and electronics. Smaller locomotives, however, must carry their gear in a car more-or-less permanently coupled to the engine. LGB locomotives that are equipped with lighting outlets (which includes most of them) can quickly and easily be radio controlled. The R/C gear is carried in a boxcar (for instance) and the leads that would normally be tied into the motor are plugged into the lighting outlet. Power is then backfed into the engine.
The locomotive should be disabled so that it cannot receive power from the rails. Sliding pickups and wheel brushes should be removed. Otherwise, you are not only backfeeding power into the engine, but into the whole track system as well, and any other trains on the line might be affected. On the more sophisticated LGB locomotives, it might be possible to damage some of the engine's internal circuitry by doing this, so check with the manufacturer first.
Very sophisticated R/C systems, like Locolinc, are now emerging. These can control not only multiple trains independently, but switches, lighting, and just about anything else you can think of as well.
Remote Control Systems of Australia has a unit designed to R/C track-powered trains. This unit is wired into the system between the power pack and the track. Full power is fed from the pack to the receiver, which then varies the voltage and polarity to the track via the hand-held transmitter. This is a useful system for those who wish to have track power, but don't want to be tied down to the spot where the power pack sits.
Many (but not all) live-steam locomotives can also be radio controlled. Some, like those made by Roundhouse Engineering, come with the radio factory installed. The principle is much the same as with electric engines, but instead of a circuit that varies the power, the receiver is hooked up to a mechanical servo that physically opens and closes the throttle and actuates the valve gear.
