Abstract: In a train control system wherein emitter beacons are located at predetermined points on the track near to one of the running rails, a device for detecting the position of a vehicle running on the railway track. It comprises into each beacon a radiating vertical-axis coil powered by an alternating current of a given frequency and, on board the vehicle, near to the corresponding rail, a pick-up unit including two pairs of receiver coils the axes of which are horizontal and perpendicular to the running rails. The associated circuits comprise two differential amplifiers connected to at least to two band-pass filters and a multiplier circuit in order to generate a positive signal when and only when the beacon is located between the two pairs of coils and the frequency of the beacon is the central frequency of the filters.

Abstract: A vital circuit network, equivalent to a two element, alternating current track relay used as a synchronous detector, has a first input transformer directly coupled across the local track circuit source and second input transformer coupled across the track rails through a band pass filter tuned to the track circuit frequency. The transformers are designed to normally produce secondary output signals of the same range, which are connected into a series circuit network including a second band pass filter, a varistor, a full-wave rectifier, and a protective fuse, with a biased track relay connected across the rectifier D. C. output. From the two voltage signals in the series network, the varistor produces a product current signal which is rectified to provide an output sufficient to pick up the track relay only when both input signals are present, are of the track circuit frequency, and are within a predetermined phase relationship.

Abstract: Insulated joint failure detectors are placed at each controlled signal location in the railroad interlocking to detect the condition of the insulated joints and also the passage of each truck of a train moving in either direction past that signal. Contacts individually responsive to detector operation serially control the lockout of cab signal transmitters to inhibit the transmission of cab signal commands within the interlocking if an insulated joint fails or an unauthorized train overruns a controlled signal. These detector contacts are individually bypassed by parallel circuit paths, controlled either by the corresponding home signal relay or cab signal control relays properly energized along an established route, in order to prevent lockout when the train is authorized to pass that signal location.

Abstract: At the remote end of a Type C track circuit, the conventional diode and the winding of a power transfer relay connected in multiple are connected across the rails over a transfer relay front contact. This transfer relay and the track relay at the near end are normally energized by the same half cycle of track current from the alternating current (AC) source. If the AC source fails, a track battery is connected across the rails at the remote end in series with the diode and transfer relay multiple network over a transfer relay back contact. The diode is so poled that the track relay is energized from the track battery with the same polarity as the rectified alternating current and does not release during the transfer operation. The diode bypasses substantially all track battery current away from the transfer relay.

Abstract: The receiver of an audio frequency (AF) track circuit for a track section of an electric propulsion railroad is coupled across an associated impedance bond by the primary and secondary windings of a saturable transformer. The control winding of this transformer receives energy signals from a voltage comparator network which compares input signals from two pick up coils, one positioned in inductive relationship with each rail at the receiver end of the section. These coils are tuned to respond to a selected ripple characteristic of the rectified DC propulsion energy, e.g., the sixth harmonic of the basic AC power supply source.

Abstract: Two sensor coils are positioned one adjacent each separate gage rail at the track relay end of a dual gage track section in which train detection current flows in the two gage, i.e., other than common, rails in parallel and returns through the common rail to the energy source. The signal induced in each sensor coil by this track circuit current is applied to a separate receiver broadly tuned to the track circuit frequency. The amplified receiver outputs are applied to a comparator unit which generates an output signal only when the inputs from the receivers are substantially equal as a result of equal other rail currents. The comparator output holds energized a broken rail detector relay which releases to indicate a broken rail condition in the other rails when the sensor coil signals differ by a predetermined amount. If possibility of a shunt fault between the other rails exists, the detector arrangement is supplemented by an audio frequency (AF) circuit in the loop formed by the two other rails in parallel.

Abstract: A track circuit receiver with a synchronous detector is provided wherein the phase of the reference voltage is caused to automatically follow that of the input voltage, so that there can be no reduction in output signal level as a result of phase differences between input voltage and reference voltage. Fail-safe operation is achieved by inverting the phase of the reference voltage and monitoring the rate of phase change at the output. The track circuit receiver of the present invention additionally utilizes simplified circuitry to achieve the foregoing.

Abstract: Vehicle identification system comprising a carrier period detector in which, to increase the accuracy of identification signals received, the identification signal is rejected and a new identification signal is requested whenever one period is absent from the carrier signal received.

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.

Abstract: A model railway or road vehicle installation in which vehicle-mounted electric drive motors are supplied through contact with track conductors, including a power supply providing an intrinsically safe a.c. component of such frequency and amplitude as to be capable of breaking down any contact inhibiting dielectric layer of dust, grease, metal oxide etc. on the track conductors, in addition to the normal d.c. component powering the vehicle. An automatic arrangement suppresses the a.c. component so long as good electrical contact is maintained so that the a.c. component is provided only when necessary. For facilitating slow speed operation, the d.c. supply is pulsed with a variable mark to space ratio dependent upon the desired vehicle speed thereby to maintain the torque output of the vehicle motor.

Abstract: A stretch of railway track, has a high frequency track circuit transmitter and receiver and a cab signal transmitter coupled across track rails at each of several locations marking the ends of track sections along a stretch of railway track. Each location has an impedance bond having a primary winding connected across the track rails and having toroid secondary windings tuned to assigned distinctive high frequencies for coupling a track transmitter and a track receiver to the track rails. A loop circuit is also provided at each location, including a tuned loop, for inductively coupling a cab signal code transmitter to the track rails independent of the impedance bond. The tuned toroid coils and the loop circuit are connected in series to one end of a two wire line circuit, which, at its other end, is connected to a track circuit high frequency transmitteer, a track circuit receiver, and a cab signal transmitter connected in multiple.

Abstract: A transmitter and a receiver are located at each junction location between adjoining track sections along a stretch of track for transmitting and receiving cab signal or speed control commands through wire loops laid in a preselected pattern parallel to and between the rails of each section. Train carried apparatus is selectively reponsive to the speed commands and to the pattern of the wire loops to control the movement of the train in the established direction through the stretch. A distinct directional frequency is transmitted from the selected entrance end of the stretch, when a train movement is desired, and is repeated at each wayside location through the wire loops to the exit end. The directional frequency reception at each location activates a filter output to selectively enable gating elements to connect the associated transmitter and receiver to the adjoining section loops in accordance with the desired traffic direction.

Abstract: A wire loop for carrying cab signal or speed control commands is laid parallel to the rails along the track center line except at the exit end of each section where an offset portion of this loop is laid immediately adjacent one rail to form a cut-in signal source. A second loop is laid along the center line of the rails through this offset distance, which is equal to the stopping distance of the train from the restricted speed rate, and each loop is supplied by the same cab signal transmitter. Each train carries receiver coils positioned above the center line loops and above the cut-in loop positions. The normal cab signal or speed control apparatus is controlled by the signal picked up by the receiver coil above the centerline loops in the track. A separate cut-in receiver is controlled by signals picked up from the offset portion of the main loop but responds only to a proceed signal command.

Abstract: A high pass coupler or filter network provides a bypass for relatively high frequency AC signals, while providing DC signal isolation and avoiding loading the track for relatively low frequency AC signals, around a set of insulated joints in a railroad track or the like. The high pass coupler includes a coupling portion for connection to a track and a dynamically resonant filtering portion with a selectable low cut off frequency determined by the proper size capacitor. The capacitor sets up resonance with the track inductance, which decreases in magnitude in response to the moving shunt affect of a train approaching the coupling portion and thus increases the resonant frequency of the coupler, and the capacitor is of a magnitude that ensures the coupler resonant frequency will not exceed the frequency of the AC signals normally to be passed by the coupler.

Abstract: Alternating current track circuit energy for train detection and cab signals is coupled to the exit end of an insulated, dual gage track section between the common rail and the other two rails connected in parallel. The track relay is connected at the entrance end in a similar manner. Impedance bonds for direct current propulsion are also connected between the common rail and the other two rails at each end. In all forms, the propulsion return current is sufficiently balanced between the three rails to eliminate cab signal interference in either gage. In a first arrangement, a direct wire connection multiples the two other rails at each end. Impedance bond taps to complete the return circuit provide a two to one turn ratio from the common rail end of the bond winding to equalize the propulsion current ampere turns on each side of the tap and thus balance the flux generated.

Abstract: Separate traffic and block clear indication line circuits control either direction train movements through a stretch of track under cab signal indications without intermediate wayside signals. Reversible phase sensitive track circuits provide train detection and cab signal energy. A block clear, opposing locking repeater relay and a traffic route request relay at the selected entrance end of the stretch control the traffic line circuit to initiate traffic reversal operations. The magnetic stick traffic relays are shunted by a back contact of a neutral line relay to protect against lock out of the traffic line circuit by external voltage surges. The direction of the block clear line circuit is established by the traffic relay position. This second line circuit also checks the track sections unoccupied, the opposing signal, and traffic locking conditions before energizing a block or super-clear relay at the entrance end of the traffic stretch.

Abstract: A signal bandpass filter apparatus is disclosed wherein a direct short circuit between input and output is prevented and the loss of the ground reference of the filter is detectable and fail-safe in operation.

Abstract: Method and apparatus for central spacing control of track-operated vehicles, particularly railroad vehicles, along paths which are subdivided into individual track sections for the positioning of the vehicles, which sections are continuously monitored as to occupation, in dependence upon the instantaneous position of the vehicles, preferably utilizing stationary information systems, particularly for railroad systems with a dense train succession and track section lengths, and without continuous information channels between vehicles and a main office, in which each of the track sections is continuously monitored in the main office, with respect to occupation thereof by a vehicle or a series of coupled vehicles, to determine whether the path sections ahead of and/or behind the occupied distance, representing a predetermined minimum distance between successive vehicles or series of coupled vehicles, are free of vehicles, and providing an actuating signal, when a section indicated as occupied is within the path r

Abstract: A signaling system for cars having wheels adapted for running along a track, in which a signal wire is disposed to extend along the track, a pantograph is provided on each car to make sliding engagement with the signal wire, and a detector apparatus responsive to the sliding movement of the pantograph along the signal wire is provided to detect the relative interval between the cars.

Abstract: The control system operates vehicles over a right-of-way divided into a plurality of zones and selects the direction of traffic along the right-of-way. The presence of a vehicle is sensed when it enters the zone from either direction and the occupancy of the zone is registered. The occupancy registration is indicated by a magnetically actuated switch to operatively control restrictive aspects in accordance with selected number of zones behind the leading vehicle relative to the selected direction of traffic.

Abstract: A railway signal system detects a train approaching the system tie points to a railroad track by transmitting in the track a modulated AC carrier wave signal, which is attenuated by the variable shunt effect of an approaching train, and monitoring the track signal in a receiver that responds to signal variations caused by such an approaching train to drop a signal relay, which operates a gate, flasher, or the like at a grade crossing. The track signal is normally automatically regulated to be within a voltage window, and a continuous system latch up feature precludes pick up of the signal relay upon occurrence of a broken rail or high track signal, for example, caused by a very high impedance ballast, until manually reset. A time delay circuit delays pick up of the signal relay after motion has been first detected, and a bypass circuit for a low track signal detector allows system operation even after an unexpected shunt occurs on a monitored section of track.

Abstract: A frequency selective filter is connected between the track transformer and phase selective unit at the receiving end of a coded phase selective track circuit to reject interfering signals of propulsion current frequency. The series L-C filter comprises a capacitor and a two-winding reactor coil with a resistor permanently connected in series between the two windings. Each winding is tapped to allow a selection of the filter inductance to match track circuit impedance, including impedance bonds and ballast resistance. Taps for short track circuits include the second winding and the resistor to improve signal to noise ratio. Energy for short interlocking track circuits is of a higher frequency, and a special tap on the first winding is selected to enable filter tuning at this other frequency for train detection since basic frequency is still used during code off-time for cab signal control.

Abstract: An antenna apparatus is disclosed for improved coupling of audio signals in relation to the vehicle track of a transit system operative with steel rails and providing a reduced cost for the associated hardware and lower crosstalk with adjacent signal blocks and track rails.

Abstract: An improved train vehicle speed control system is provided for operation in conjunction with train speed control signals and train occupancy indication signals in relation to a train vehicle track system including a plurality of predetermined track circuit signal blocks through which train vehicles pass. It is desired that a control of train vehicle speed be provided in relation to the detected occupancy by a train vehicle of a particular signal block, for maintaining train vehicle occupancy protection requirements and providing desired sequential occupancy control of the train vehicles through each of successive signal blocks through operation of provided protection signals with selected signal blocks behind the detected train vehicle. Spurious pseudo vehicle occupancy in a given signal block is detected and included in the provided train speed control in relation to that given signal block.

Abstract: A collision avoidance system adapted for railroad use comprising a track having connected thereto a plurality of first signal transmitters exciting the track by a first control signal within a first frequency bandpass range and a plurality of second signal transmitters interspaced between the first signal transmitters in an alternating arrangement, such second transmitters exciting the track by a second control signal within a second frequency bandpass range. While the first and second control signals are respectively within the first and second bandpass range, individual ones thereof are separated by frequency increments from the other control signals within the corresponding bandpass range such that any beats therebetween are of a relatively high frequency.

Abstract: There is disclosed a double rail track circuit for use within a railroad block or each cut section of a block. Adjacent cut sections, or blocks, are separated by insulated rail joints. A transmission line having terminals accessible at each joint is provided. The transmission line has impressed thereon a modulated carrier signal to provide a reference signal at the modulation frequency. The reference signal derived from the carrier is coupled to one end of each block, or cut section, in such a manner that the signals of adjacent blocks, or cut sections, are out of phase with respect to each other. A synchronous detector is coupled between the transmission line and the rails at the other end of the block, or cut section, to compare the phase of the signal at the other end, with the anticipated signal phase. Band-pass filters may be used between the rails and the synchronous detector and between the transmission line and the synchronous detector and which do not pass common frequencies.

Abstract: This invention relates to a signal system for high speed vehicles traveling along a predetermined way. In the system vehicles are controlled from the wayside through the use of incremental signals automatically provided to the vehicles as a function of vehicle passage and relative vehicle position. In addition central control is provided for such a system to allow for superimposing on the automatic wayside signal equipment a programmable speed control which allows for simultaneous provision of safe vehicle speed while establishing constant, acceleration or deceleration control over any vehicle in the system.

Abstract: A receiver is disclosed which is used in a transportation vehicle detection system to compare logic conditions in signals which are transmitted from a first vehicle pathway location, with logic conditions which are detected from signals received at a second vehicle pathway location. When first and second enable signals correspond, the signal from an oscillator is transmitted through two pairs of fail-safe AND gates and applied, through a fail-safe OR gate, to a latch circuit which signals the transportation system speed controller that no vehicle is present between the first and second pathway locations. When the first and second enable signals do not correspond, the signal from the oscillator is not transmitted through both pairs of fail-safe AND gates, there is no signal applied to the fail-safe OR gate, and no signal is applied to the latch circuit which signals the transportation system speed controller that a vehicle is present between the first and second pathway locations.

Abstract: There is disclosed an input signal threshold responsive apparatus for responding to a predetermined input signal energy level, in relation to a voltage and time product, before an associated train vehicle control system is enabled by a provided gated enable signal. The provided apparatus responds to one of a plurality of input signals, having respectively different frequencies and different amplitudes, and provides an enabling output signal.It is desired to provide an improved threshold sensitive input signal receiver apparatus in conjunction with train vehicle control and in relation to plural stray signals in a given track circuit signal block due to cross talk from adjacent signal blocks and the like. The input signal responsive or sensitivity threshold is established in relation to the practical required signal level of the desired signal to be received within the given signal block.

Abstract: A variable permeability magnetic object detection device including an electromagnetic sensing coil; a core disposed in the electromagnetic sensing coil having a first permeability when the core is magnetically saturated and a second different permeability when the core is magnetically unsaturated; a magnetic member proximate the electromagnetic sensing coil for providing a magnetic field in the core for operating the core in a magnetically saturated state without a magnetic object to be detected present in the area proximate the electromagnetic sensing coil, interacting with the magnetic field, and for operating the core in a magnetically unsaturated state with the magnetic object to be detected present in the area proximate the magnetic sensing coil, interacting with the field; and a detector responsive to said electromagnetic sensing coil to detect the presence of a magnetic object.

Abstract: An improved train vehicle speed control system is provided for operation in conjunction with train vehicle occupancy control signals and train occupancy indication signals in relation to a train vehicle track system including a plurality of predetermined track circuit signal blocks through which the train vehicles pass. It is desired that control of train vehicle speed be provided in relation to the detected occupancy by the train vehicle in a particular signal block, for maintaining train vehicle occupancy protection requirements and providing protection signals to establish desired sequential occupancy control of the train vehicles through each of selected signal blocks adjacent to that particular signal block. Spurious pseudo vehicle occupancy in any signal block is detected and included in the provided train speed control in relation to that signal block.

Abstract: There is disclosed a train vehicle protection apparatus including the determination of train vehicle occupancy of a track circuit signal block, wherein a frequency tone speed code signal is provided to the signal block for controlling the train vehicle speed and a vital and fail-safe determination of train vehicle occupancy of the signal block is provided.

Abstract: A signaling circuit adapted to be used with railroad tracks or the like for ensuring fail-safe performance in respect to the operation of a control device, such as a track relay, which must function in a fail-safe manner, typically to become deenergized after a set period and to release or drop away when any emergency or failure occurs; thereby to produce a safe action, such as providing a warning signal to the engineer or operator of a train. The signaling circuit includes a quick-acting shunt detector which operates to detect short-duration shunting effects and functions to so extend or enhance them that they produce the desired result of releasing the track relay.

Abstract: A detective circuit for railway points composed of three track sections connected together at a junction or for a railway crossing composed of four track sections connected together at a junction.

Abstract: An antenna apparatus is disclosed for coupling audio frequency signals in relation to one or more vehicle track rails of a transit system for the purpose of determining vehicle occupancy of a given signal block and providing speed coded control signals to a vehicle moving along the track rail in that given signal block. It is desired that each signal block in the transit system track circuit operate with the signal level above a predetermined minimum signal level for reasons of vehicle occupational detection. The antenna apparatus is operative to enable desired adjustment of the signal level in a given signal block and in adjacent signal blocks relative to that given signal block.

Abstract: A single relay serves to register route request selections for both traffic directions over each track route through a railroad interlocking layout. This single route request relay is jointly controlled by the route selection push buttons for both directions, the actuated push button being also repeated by a traffic direction relay. The route request relay pick up checks that no conflicting route request is active, and that the same or opposing route is not already established and locked. The route request and direction repeater relays are held by stick circuits to store the request until the route is locked. A single relay serves to provide the clear and lock function for all possible traffic routes originating at each entry point into the interlocking.

Abstract: In a railroad interlocking, a cab signal transmitter is coupled to the rails at each exit location and at such other locations as are necessary to supply continuous cab signal energy to trains traversing any possible route through the interlocking. Where train shunts prevent the reception of cab signal energy, wire loops laid adjacent the rails carry the cab signal energy for train pickup. Each rail coupled transmitter is finally activated to supply energy when a train occupies an associated track section. However, the control circuit network for each transmitter also checks, as pertinent for the established route, that a route has been established and the approaching train authorized to traverse that route, that any succeeding track sections along the route are unoccupied, that the transmitter for a preceding section has been activated, and that transmitters for opposing or conflicting routes are not active.

Abstract: To identify a moving car for switching it from a main line to a spur, a signal indicator on the car tuned to a selected frequency activates a signal pickup apparatus which is located on the main line ahead of the spur. The signal pickup apparatus emits a radiation field sweeping a range of frequencies including the same frequency as that of the signal indicator. The signal pickup apparatus includes circuitry which responds to the activation by the signal indicator to operate the switch of the spur for the diversion of the moving car.

Abstract: A variable permeability magnetic object detection device including an electromagnetic sensing coil; a core disposed in the electromagnetic sensing coil having a first permeability when the core is magnetically saturated and a second different permeability when the core is magnetically unsaturated; a magnetic member proximate the electromagnetic sensing coil for providing a magnetic field in the core for operating the core in a magnetically saturated state without a magnetic object to be detected present in the area proximate the electromagnetic sensing coil, interacting with the magnetic field, and for operating the core in a magnetically unsaturated state with the magnetic object to be detected present in the area proximate the magnetic sensing coil, interacting with the field; and a detector responsive to said electromagnetic sensing coil to detect the presence of a magnetic object.

Abstract: A signal bandpass filter apparatus is disclosed wherein a direct short circuit between input and output is prevented and the loss of the ground reference of the filter is detectable and fail-safe in operation.