Hump yard retarder control system

Claim 1

In a system for controlling the speed of a railroad car rolling, under the influence of gravity, down an inclined track and onto one of a plurality of destination tracks, the combination which comprises: a. a car retarder located along the rails of the inclined track and selctively operable between a braking position wherein the car wheels are engaged as the car progresses through the retarder toward an exit end thereof, and a non-braking position; b. a retarder contrOl mechanism responsive to electrical signals and connected for actuating said retarder to move it between braking and non-braking positions; c. a first means positioned uphill of said retarder, said means producing electrical output signals indicative of the car speed as it approaches said retarder; d. a second means positioned adjacent said retarder and producing a plurality of separate electrical output signals each indicative of the car speed at a respective one of a plurality of positions of the car within said retarder; e. a weight responsive means positioned in the inclined track uphill from said retarder to produce electrical output signals indicative of the weight of the car approaching said retarder; f. track circuit means associated with each of the plurality of destination tracks to produce electrical output signals indicative of railroad car occupancy on each of the destination tracks; and g. a digital computer connected to receive, as electrical input signals, the electrical output signals of said first means, said second means, said weight responsive means, and said track circuit means, said computer being programmed to constitute a means for i. receiving said input signals from said first means, said weight responsive means and said track circuit means to compute an exit speed which the car should have as it leaves the exit end of said retarder so as to cause a car to arrive at the one of the destination tracks with a desired speed, ii. utilizing the series of separate electrical output signals from said second means to compute from each input signal the car speed and location of the car within said retarder at the time each speed measurement is taken, iii. computing a projected speed and location for the car as of a later time after each such time of measurement, the interval of time between the time of actual speed measurement and the later time being determined in the computer in dependence on parameters established by the dynamics of said car retarder, iv. comparing the computed projected values with further computed values, for such later time, which further computed values are those required to achieve a uniform rate of deceleration of the car through the effective length of said retarder, said uniform rate of deceleration of said car being computed from the measured speed of the car as it enters said retarder and the computed exit speed, and v. transmitting electrical signals to said retarder control mechanism to move said retarder to its braking position, or to its non-braking position, in dependence on whether the computed projected speed is above or below, respectively, that of the computed speed which is required, at the projected location, to achieve the desired uniform deceleration rate for the car.