Signaling techniques for DC track powered model railroads

Electronic circuits and methods are provided for remote control of a locomotive in a model railroad layout having an interruptible DC power supply coupled to the railroad track. The locomotive motor is isolated from the track so as to allow use of polarity reversals on the track power signal for controlling remote effects in the locomotive such as sound effects. An on-board electronic state generator is provided in the locomotive for maintaining one at a time of a predetermined set of states, at least one of the states having a corresponding remote effect associated therewith. Remote control signals such as a reverse in polarity of the DC track power signal are used to clock the state generator to a desired state, thereby permitting control of a plurality of remote effects using only the traditional DC power supply interface. The locomotive motor is controlled by a motor reverse unit so that the motor direction is controllable independently of the polarity of the DC power signal applied to the track. Accordingly, both motor direction and remote effects are controllable using only the throttle and polarity reversal switch which are available in known DC model railroad power supplies.