Abstract: An automatic speed control system for a consist of diesel locomotives conserves fuel by throttling back trailing engines and operating remaining engines at the most efficient throttle position. A control unit in the lead locomotive is operated by the engineer to command control units in equipped trailing locomotives of the consist. In the lead locomotive, depressing a "set speed" push button causes a speed memory to store the existing speed of the consist, and a cutout control signal is generated which is transmitted to trailing units in serial order, i.e., front to rear, by a single spare trainline wire. The control signal has two control voltage levels that increase or decrease with deviations of the speed of the consist from the desired speed in memory. These voltage levels are decoded by each trailing unit and, if power is needed, the engine throttle is set at the most efficient position or, if the locomotive is to be cut out, the throttle is set at a desired minimum position.

Abstract: A high pass coupler or filter network provides a bypass for relatively high frequency AC signals, while providing DC signal isolation and avoiding loading the track for relatively low frequency AC signals, around a set of insulated joints in a railroad track or the like. The high pass coupler includes a coupling portion for connection to a track and a dynamically resonant filtering portion with a selectable low cut off frequency determined by the proper size capacitor. The capacitor sets up resonance with the track inductance, which decreases in magnitude in response to the moving shunt affect of a train approaching the coupling portion and thus increases the resonant frequency of the coupler, and the capacitor is of a magnitude that ensures the coupler resonant frequency will not exceed the frequency of the AC signals normally to be passed by the coupler.

Abstract: The operating mechanism of a railroad crossing gate employs a variable mechanical advantage connection to transmit force from the drive motor to the gate member to raise and lower the same. The main shaft of the mechanism serves as a mount for the gate member and its counterweights, and an operating arm is fixed to the shaft and extends radially therefrom. A crank is driven by reduction gearing and is connected to the arm by a sliding coupling which reciprocates on the arm longitudinally thereof as the crank rotates. The axis of rotation of the crank is located such that the mechanical advantage is high when the gate member is in either its raised or its lowered position, decreasing to a ratio approaching unity at the midpoint of travel in either direction. Accordingly, the starting load is minimized, the gate member is accelerated once it is in motion, and its speed is then reduced as it nears the end of its travel.