Abstract: A switch machine that includes a first relay having first normally open contacts and first normally closed contacts provided in the normal motor connection path and a second relay having second normally open contacts and second normally closed contacts provided in the reverse motor connection path. The normally open and closed contacts of each relay are associated in pairs and the first relays are structured such that each normally closed contact and the corresponding normally open contact cannot be simultaneously closed. Also, a method of protecting a motor of a switch machine that includes integrating a current being drawn by the motor and opening a motor circuit that includes the motor if the integrated current exceeds a threshold.

Abstract: A switch machine that includes a first relay having first normally open contacts and first normally closed contacts provided in the normal motor connection path and a second relay having second normally open contacts and second normally closed contacts provided in the reverse motor connection path. The normally open and closed contacts of each relay are associated in pairs and the first relays are structured such that each normally closed contact and the corresponding normally open contact cannot be simultaneously closed. Also, a method of protecting a motor of a switch machine that includes integrating a current being drawn by the motor and opening a motor circuit that includes the motor if the integrated current exceeds a threshold.

Abstract: A method provides sleep and wake-up modes for railway track circuit units. An intermediate track circuit unit communicates in a first direction to a first unit and in a different second direction to a different second unit. A plurality of wireless messages are employed between a train and a plurality of wayside units operatively associated with some of the track circuit units. Included with the wireless messages are a first identifier of a corresponding one of the track circuit units and a second identifier of a direction of travel of the train. One of the wireless messages is received at one of the wayside units corresponding to the intermediate unit based upon the first identifier. A signal is responsively output based upon the second identifier from the intermediate unit in the first direction to the first unit or in the different second direction to the different second unit.

Abstract: A railroad signaling method includes measuring a track current on a first track section, measuring a local voltage on the railroad line wires, determining whether a magnitude of the track current meets or exceeds a threshold value independent of the local voltage, and determining whether the track current and the local voltage are nominally in phase with one another in a manner that is independent of the track current measuring step. A first signal is provided only if the magnitude is determined to meet or exceed the threshold and the track current and local voltage are determined to be nominally in phase. The first signal is an indication that a train is not present in the track section, that the track section does not have a broken rail, and that the insulated joints that bound the track section do not include a fault condition. An associated relay arrangement is also provided.

Abstract: A solid state code following track relay receives pulsating rail current from a railway code transmitter. The track relay includes first and second inputs structured to receive the rail current. Two Hall effect digital current sensors each have a coil and an output, which responds to current flowing through the coil. The coils of the current sensors are electrically connected in series between the first and second inputs and are structured to receive the rail current. The outputs of the current sensors are structured to turn on and off in response to the rail current. A circuit including dual one-shot multivibrators, which are triggered by positive and negative going edges from the respective current sensors, and a flip-flop, which is set and reset by the outputs of the respective multivibrators, determines that each of the current sensors is functional. Two solid state outputs are structured to follow the rail current.

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 method of point detection is for use with a railway switch machine including a housing, a point detector bar positionable in a normal point position and a reverse point position, and a slide lock bar positionable in a normal locked position and a reverse locked position. The method includes providing point detecting sensors in the housing adjacent the point detector bar; detecting with the point detecting sensors the position of the point detector bar; generating by the point detecting sensors a point detection signal representative of the position of the point detector bar; and delivering the point detection signal to a processing device for determining if the point detector bar is in the normal point position, the reverse point position, or in neither the normal point position nor the reverse point position.

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 point detection system for a railway switch machine having a housing includes a point detector bar positionable in a normal point position and a reverse point position, and point detecting means positioned within the housing for detecting when the point detector bar is in the normal point position and when the point detector bar is in the reverse point position. The point detecting means may include a first proximity sensor for detecting when the point detector bar is in the normal point position and a second proximity sensor for detecting when the point detector bar is in the reverse point position. Preferably, the first proximity sensor and the second proximity sensor are inductive proximity sensors. A method of point detection for a railway switch machine is also provided.

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 point detection system for a railway switch machine having a housing includes a point detector bar positionable in a normal point position and a reverse point position, and point detecting sensors positioned within the housing for detecting when the point detector bar is in the normal point position and when the point detector bar is in the reverse point position. The point detecting sensors may include a first proximity sensor for detecting when the point detector bar is in the normal point position and a second proximity sensor for detecting when the point detector bar is in the reverse point position. Preferably, the first proximity sensor and the second proximity sensor are inductive proximity sensors. A method of point detection for a railway switch machine is also provided.

Abstract: The vital driver utilizes rectification and subsequent synchronized inverting of the rectified power, which is then fed to a transformer. Failed operation, which permits current having a DC component to reach the load transformer, causes an increase in the current which is sensed by a current sensor. The high current can be detected by a fuse. Some embodiments use primary modules having a rectifier section with sufficient power to run a number of secondary units, each powering an individual load. The synchronizing inverter can utilize optically coupled solid state switches.

Abstract: An apparatus and method for supplying cab signal to a rail vehicle on a section of track composed of sequentially adjacent railway track circuit blocks. Respective receivers of each track circuit block are monitored for the presence of a vehicle within that block. The cab signal apparatus is controlled to transmit a signal to a block when the output from the respective receiver in that block indicates a different condition from the adjacent receiver of an adjacent block. Output voltages from adjacent receivers are compared to enable transmission of a cab signal. Comparison of adjacent receiver outputs is accomplished through use of a diode bridge.

Abstract: A railway vehicle cab signalling system providing electrical signals to operate an aspect display unit or the like located on-board a railway vehicle based upon the track circuit signals typically used to operate wayside indicators. A sensor detects the track circuit current as it passes through at least one wheel and axle set on the vehicle. A processor receives an output signal from the sensor and produces a signal to operate the aspect display unit.

Abstract: A railway track circuit for protection of an extended track block having a master unit at one end of the block and a satellite unit at the other. Each master and satellite unit having transmitting and receiving capabilities. The output impedance of the transmitters or of the receivers is of a low impedance as connected to the rails. Through an alternative transmit and receive sequence a link-up between the master and satellite units provides detection of broken rail and/or shunts from each end of the track circuit. The use of low impedance and detection at both ends of the section permit extended length track circuits.

Abstract: An improved audio frequency track circuit system utilizes a synchronous train detection arrangement and reduces the number of fixed code rate modulated carrier signals. As few as two carrier signals are alternately applied at discrete points along a pair of jointless track rails to define the transmitter ends of the track sections, with complementary receivers defining the opposite ends. The two carrier signals are coded at one of two phase angles which are 90.degree. out-of-phase so that, when assigned, the nearest possible interfering signal is 90.degree. out-of-phase and is rejected thereby. Like carrier frequency transmitter/receiver arrangements are disposed on opposite sides of an insulated joint but are coded 180.degree. out-of-phase so that a breakdown of the insulated joint is detected and the false code signal is rejected.

Abstract: A center-fed track circuit arrangement for an electrified section of railroad track. A first and a second remotely located insulated joint defining the limits of the track circuit. A first impedance bond connected across the rails of the railroad track in the vicinity of the first remotely located insulated joint. A second impedance bond connected across the rails of the railroad track in the vicinity of the second remotely located insulated joint. A third impedance bond connected across the rails of the railroad tracks intermediate the first and second remotely located insulated joints. Each of the first and second impedance bonds includes a center tapped winding for accommodating propulsion current. A pair of tuned windings for accommodating at least two train detection signals having different frequencies. An untuned winding for exhibiting a low impedance at the frequency of a cab signal so as to mitigate leakage current across a broken-down insulated joint.

Abstract: An analog speed error signal, developed by comparing actual and desired speeds, is processed into a control voltage through a two condition circuit network. When the error signal is more than a predetermined percentage of the desired speed, the network has a unity gain and the control voltage equals the error signal. When the error signal becomes less than the predetermined percentage, the network is shifted into a hybrid form by inserting an integrator loop into the gain circuit so that the control voltage and error signal are not directly proportional. The control voltage is converted into a series of proportional width pulses which are applied to vary the generator output to control locomotive speed. The pulse width varies in part from the error signal variation but also in part from an acceleration signal to anticipate the achievement of desired speed. When the hybrid network is in use, the pulse width speed control feeds back to drive the error signal to zero.