Sab Harmon Industries, Inc.

Daniel L Turner

Calvin D Wilde

The number of on-line locomotives of a consist is either reduced or increased by a manual control system that conserves fuel by throttling back trailing locomotives and operating the remaining locomotives of the consist 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. Each time the engineer depresses a 'subtract power' push button, one trailing locomotive is throttled back; conversely, each time an 'add power' push button is depressed, a trailing locomotive is returned on line by advancing its throttle to the most efficient position. A cutout control signal, which is generated in the lead locomotive and transmitted to trailing units in serial order (front to rear) by a single spare trainline wire, has voltage levels that progressively decrease or increase in response to the subtract or add power commands. These voltage levels are decoded by each trailing unit and the throttles are set accordingly. The trailing units also cause these voltage levels to drop by a fixed amount as the control signal is conducted by the trainline wire rearwardly in the consist from each trailing unit to the next succeeding trailing unit. In this manner, locomotives are successively throttled back from the rear of the consist and returned on line from the front. An interrogation signal is periodically transmitted along the trainline, and the trailing units respond sequentially to report the on-line or off-line status of the locomotives. Once a report indicates that a trailing locomotive has been cut out or put on line, the lead unit ceases the progressive change in the control signal voltage levels.

Power selection system for a consist of locomotives

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. The trailing units also cause these voltage levels to drop by a fixed amount (equivalent to a predetermined speed increase) as the control signal is conducted by the trainline wire rearwardly in the consist from each trailing unit to the next succeeding trailing unit. In this manner, engines are successively throttled back from the rear of the consist and returned to the higher throttle position from the front to maintain the desired train speed. A hold mode permits the automatic control system to be temporarily disabled without clearing the speed memory or changing the control signal, and depressing a 'resume speed' push button on the lead unit reestablishes automatic speed regulation.

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Belmont, CA, United States of America

Daniel L Turner