Abstract: A system and method for selectively dealing with failures in a railway signaling and control context such that only an output device or group of devices is turned off, rather than a whole system being shut down.

Abstract: A signaling and traffic control system which is capable of a vehicle determining its own absolute position along a guideway based on information received from the wayside using an inductive loop or beacon system in conjunction with the distance traveled according to the onboard tach generator(s), and report its position to a wayside control device, whereby the wayside control device reports to the vehicle, as part of its communications message, the location of the closest forward obstacle. Based upon this information, the vehicle controls itself safely based upon its characteristics as contained in a topographicla database and a vehicle database.

Abstract: A railway signalling system uses coded electrical information signals to convey vital signal information to wayside signal locations. The coded information signals are in the form of unipolar three-pulse DC signals capable of being sent or received during a 1.4 second transmission or receiving cycle. The system establishes greater signalling capability than prior systems which used only a two-pulse DC signal.

Abstract: Highway crossing protection equipment which operates warning lights or crossing gates is controlled from the train locomotive which enters into an interchange of messages via a radio link with the controller at the crossing. If communication is not established before the train reaches a safe braking distance, the brakes are applied and the train is not permitted to travel into the crossing. Communications between the train and the crossing controller is initiated by the locomotive when it passes a trackside beacon transponder located beyond a safe braking distance from the crossing. The crossing controller transmits a message addressed to the train acknowledging the receipt of the train signal. The message from the crossing controller causes the train to send a subsequent message within a minimum time which is used to update a timer (a minimum time) for the crossing to be actuated to its safe condition.

Abstract: Highwasy crossing protection equipment which operates warning lights or crossing gates is controlled from the train locomotive which enters into an interchange of messages via a radio link with the controller at the crossing. Communications between the train and the crossing controller is initiated when the locomotive passes a trackside beacon transponder located beyond a safe braking distance from the crossing. The crossing controller transmits a message addressed to the train acknowledging the receipt of the train signal. The interchange of messages can be repeated a plurality of times; each time the minimum time being updated so that traffic flow across the crossing is handled efficiently with minimum interference.

Abstract: A system for automatic operation of rapid transit vehicles in a railway yard. The vehicles have a receiver system which is responsive to information communicated thereto and a control system responsive to the receiver system for controlling the continued operation of vehicle. The invention includes: a first entry/exit track circuit having at least one transmitting system for transmitting vehicle control information to vehicles within its section of the first entry/exit track circuit, and at least one switching system for reversing the first entry/exit track circuit; a second entry/exit track circuit having at least one transmitting system for transmitting vehicle control information to vehicles within its section of the second entry/exit track circuit, and at least one switching system for reversing the second entry/exit track circuit.

Abstract: Broken rail detection in a block of track without the need or expense of conventional signalling uses a chain of transmitters and receivers connected to the rails and defining sections of the block between the ends of the block. Either cyclically at a predetermined code rate or upon command of an external unit; an alternating current (AC) signal is launched from one end of the block and is repeated at different frequencies in each of the sections. When received at the end of the block, an indication of the absence of a broken rail condition is given either (a) by way of pole line or radio communication to a central control or dispatcher point and thence back to the trains, or (b) signals at the ends of the block are flashed at the code rate. The detected signal at the code rate may be used to modulate a direct current which is transmitted along the rails in the block to a signal at the opposite end of the block which also flashes at the code rate to indicate a safe condition.

Abstract: A railway signaling and traffic control system which minimizes the wayside equipment and eliminates the pole lines which carry power and signals along the right-of-way using instead the radio channel between the trains and the central office. Each train communicates with devices, such as passive beacons, which provide zone boundary messages. These devices provide secure messages to a control unit containing a microprocessor which responds to zone boundary messages and provides location information to the central office via radio when the train enters and leaves each zone. The central office has an input and communication processor and a vital processor. The vital processor converts route requests and the zone occupancy messages which are received by the input and communications processor into messages representing the signal aspects (the maximum speed at which the train can proceed), not only for the zone currently occupied, but also for the zone next ahead.

Abstract: A railway track switch, also known as a switch machine, is controlled by a microprocessor switch lock connected to the electric switch lock of the switch machine and permits the switch machine to be unlocked so that the track switch points may be thrown, as by a hand-throw mechanism, to permit movement of a train between main and secondary tracks. The switch lock is connected to a cut section repeater of the track circuit adjacent to the track switch. An overlay track circuit connected to the main tracks indicates occupancy in the vicinity of the track switch. The microprocessor receives signals from the repeater, the overlay circuit and the electric switch lock of the switch machine indicating track occupancy and requests to unlock the track switch so that the switch points may be moved. Signals are also received from a timer as to specific, selected delay times set by the user before unlocking the switch.

Abstract: A railroad train detector and communication system relies on the track rails for communicating information among a plurality of locations. The equipment located at each of the locations eliminates relay based current detection, relay based current transmission, and relay based logic functions, and rather these functions are implemented with microprocessors. An extent of signal trackway is defined between a pair of head ends, intermediate the head ends at intermediate insulated joint locations, a microprocessor implemented transmitter/receiver pair is provided. One half of the transmitter/receiver pair manages communication flow for each direction of information flow at the joint. At each of the head locations, only a single transmitter/receiver is required. Associated with each microprocessor in a transmitter/receiver is auxiliary apparatus to couple the microprocessor's input/output ports to the track rails themselves.

Abstract: A receiver for sensing track currents includes a toroid coupled to the track rails via a single conductor. The toroid has an air gap in which a linear Hall sensor is inserted. The voltage of the Hall sensor is applied to signal processing circuitry including a low pass filter, amplifier and level detectors. In one embodiment of the invention comprising a track occupancy detector, second and third windings coupled to the toroid are selectively energized from a potential source to provide MMF's in the toroid of one and another polarity, and of a level less than the MMF provided by an occupied track section. The amplifier includes first and second channels for amplifying signals of opposite polarities. Each channel of the amplifier is coupled to a pair of level detectors, one of the level detectors in each pair is a vital level detector with the threshold set at about 50% of the threshold of the other level detector in the pair.

Abstract: Alternating current track circuits are provided for the several adjoining track sections of a stretch of railway track, each of the track circuits comprising an alternating current code transmitter and an alternating current code receiver connected to track rails at opposite ends of the associated section. Circuit apparatus including an alternating current line circuit extending along the stretch of railway track is provided for normally communicating alternating current from the line circuit through rails of the associated track sections, the alternating current being modulated at a selected rate code and current in any two adjoining track sections being of opposite instantaneous polarity for broken down joint protection. Phase sensing apparatus is provided at a receiving end of each track section including a comparator for comparing the rate code modulated alternating current communicated through the track rails with a steady reference source connected to the line circuit.