Abstract: A switch machine electronic controller includes a point detecting circuit having Namur sensors for detecting an indication rod target in first and second point positions, and a lock detecting circuit having Namur sensors for detecting a lock box target in first and second lock positions. A microprocessor processes the signals to provide Normal and Reverse outputs. The Normal output is enabled when the first point and lock detection signals have values within a predetermined ON value range, and the second point and lock detection signals have values within a predetermined OFF value range. The reverse output is enabled when the second point and lock detection signals have values within the ON value range, and the first point and lock detection signals have values within the OFF value range. Both outputs are disabled when any of the signals has a value that corresponds to a shorted, open or indeterminate value range.

Abstract: A motor control apparatus for a reversible motor of a railway switch machine includes a conditional power source having an output voltage. A motor control circuit includes inputs for inputting the voltage from the power source, inputs for inputting a normal signal and a reverse signal, two output terminals for electrical connection to two input terminals of the reversible motor, and a relay logic circuit including a pair of double pole, double throw relays. The contacts of these relays: (a) output the voltage to the two output terminals in response to the normal signal, (b) output an inverted polarity of the voltage to the two output terminals in response to the reverse signal, and (c) short the two output terminals in response to absence of both of the normal and reverse signals.

Abstract: A motor control apparatus for a railway switch machine includes a power source for a voltage; a selector for providing the voltage to a reversible motor of the switch machine in a normal state, and for providing a reverse polarity of the voltage to the reversible motor in a reverse state; a first transistor for switching reverse current flowing through the reversible motor; a first diode electrically connected in parallel with the first transistor for conducting normal current for the reversible motor; a second transistor for switching normal current flowing through the reversible motor; a second diode electrically connected in parallel with the second transistor for conducting reverse current for the reversible motor; and a circuit for controlling the first and second transistors based upon the position or operating mode of the railway switch machine.

Abstract: A signaling apparatus that includes a transmitter having a step-square wave generator for generating a signaling waveform, which waveform is composed of a plurality of square wave signals, and which has an information signal encoded thereupon. The apparatus may also include a signaling waveform receiver, disposed on the railcar, and an information signal decoder, connected to the receiver, for extracting the information signal from the receiver. The stepped-square wave generator produces square waves such that a portion of the duty cycle of one of a plurality of square wave signals overlaps at least a portion of the duty cycle of at least one other of the plurality of square wave signals. A method for signaling in which a multi-stepped square waveform is generated, includes a waveform having a series of superimposed square waves, each of which having preselected amplitudes and duty cycles. An information signal can be encoded upon the multi-stepped carrier waveform such that a coded-carrier signal is created.

Abstract: A signaling apparatus that includes a transmitter having a step-square wave generator for generating a signaling waveform, which waveform is composed of a plurality of square wave signals, and which has an information signal encoded thereupon. The apparatus may also include a signaling waveform receiver, disposed on the railcar, and an information signal decoder, connected to the receiver, for extracting the information signal from the receiver. The stepped-square wave generator produces square waves such that a portion of the duty cycle of one of a plurality of square wave signals overlaps at least a portion of the duty cycle of at least one other of the plurality of square wave signals. A method for signaling in which a multi-stepped square waveform is generated, includes a waveform having a series of superimposed square waves, each of which having preselected amplitudes and duty cycles. An information signal can be encoded upon the multi-stepped carrier waveform such that a coded-carrier signal is created.

Abstract: A vital integrated circuit square-wave oscillator having an integrated circuit operational amplifier. A reference voltage dividing resistor network connected to an inverting input of the amplifier for providing a 50--50 duty cycle. An L-C tank circuit connected between the inverting input and a noninverting input for determining the frequency of oscillation. A starting capacitor for initiating the oscillating action and a regenerative feedback circuit for sustaining the oscillations.