Abstract: A railroad crossing gate arm electrical lamp system provides two flashing lamps and one continuously operated lamp. Each of the lamps has an internal electrical circuit with the internal electrical circuits being identical for each lamp. This permits the lamps to be interchanged in position with the lamp positions determining the function of the lamp. Each lamp electricl circuit has a three-wire input connection and a three-wire output connection. There are identical and reversible three-wire cables connecting the first flashing lamp with the second flashing lamp and the second flashing lamp with the continuously operated lamp. The input for the first flashing lamp includes two power supply terminals and a third common terminal. The lamps are connected in series across the power supply and a relay alternately shunts the lamps to obtain flashing of two of the lamps. The third lamp is connected across the power supply for steady light.

Abstract: An island circuit detects the presence of a train on a crossing island, and, in response, de-energizes a normally energized relay to activate a warning. A random signature signal is generated and transmitted through the rails from a transmitter to a receiver connected to the rails on either side of the island. If a train is present within the island, the wheels and axles form an electrical shunt, preventing the receiver from detecting the transmitted signal. The circuit employs solid state micro-electronic components and ancillary components, and embedded software for controlling and monitoring the circuit functions. The random signature signal is characterized by a relatively high voltage level but a low duty cycle on the order of ten percent, and has three variables: (1) frequency; (2) duration time of the pulse, or burst, of the signal; and (3) the delay between successive bursts. Each of the three variables randomly assumes any one of eight different discrete values.

Abstract: The apparatus is provided with a unidirectional motor operatively coupled to the hinged sign through an eccentric drive by a link arm which incorporates a pre-loaded helical compression spring to prevent damage to the link arm should an attempt be made to forcibly swing the sign. Two normally-closed limit switches are associated with the link arm whereby in the course of a motor operating cycle, the stop sign is caused by the link arm to swing out to its outstretched position, at which point one limit switch opens, and then to return to its retracted position, at which point the other limit switch opens. The limit switches are included in a control circuit which supplies power to the motor. The control circuit is responsive to a door switch associated with the bus door so that when the door is open, the door switch is then closed, and power is supplied to the motor through one limit switch until the sign reaches its outstretched position, at which point this limit switch is opened to cut off the motor.

Abstract: A variable placement lamp system for use with a supporting member is disclosed which includes a plurality of lamp housings (40) each including a channel for receiving an upper edge of a supporting member. Screw (50) on both sides of the housing (40) are turned until the housing is secured to the support member in a friction fit. Extensible cables (70) with 3-pronged connections connect the lamp circuitry to electrical circuitry to operate the lamps (38) in a predetermined pattern.

Abstract: Control apparatus for a hinged stop sign mounted on the side of a school bus to cause the sign to swing out to an outstretched position when the bus door is opened to load or unload passengers and to return the sign to its retracted position when the door closes. The apparatus is provided with a unidirectional motor operatively coupled to the hinged sign through an eccentric drive by a link arm having associated therewith two normally-closed limit switches, whereby in the course of a motor operating cycle, the stop sign is caused to swing out to its outstretched position, at which point one limit switch opens, and then returns to its retracted position, at which point the other limit switch opens. The limit switches are included in a control circuit which supplies power to the motor.

Abstract: A railroad crossing lights/gate controller for effecting operation of the crossing lights and lowering of the crossing gate during normal train operating conditions and during a gate controller failure mode includes a train sensing input, a gate control circuit, a lights control circuit, a solid state logic and monitor circuit and a fail/safe relay. The train sensing input provides one signal condition when the approach of a train is sensed and another signal condition when no train is sensed. This input is connected to the solid state logic and monitor circuit which is also connected to the gate control circuit and the lights control circuit. The gate control circuit has power applied thereto to maintain the gate in a raised position when the train sensing input indicates a no train condition and the lights control circuit has power supplied thereto to operate the lights in a flashing condition when the train sensing input indicates the approach of a train.

Abstract: To ensure the safe operation of an electronic circuit, for example an amplitude modulated carrier signal generator, an output of the circuit is analyzed to prove the presence of predetermined signal characteristics, for example the carrier signal, or a modulation frequency. The predetermined signal alternatively may be superimposed on an input to the electronic signal and proved subsequently to be present in the output. The output of the circuit is passed inhibited, according to whether or not the signal characteristics are proved present, by means of an output enable gate which is self-latching providing the output continues to be proved correct. A start-up circuit delays a possible inhibit for a limited period following initial power connection to the circuit in order that the output can become established.

Abstract: A railroad crossing gate (20) is disclosed having a novel crossing arm (24) which includes a first longitudinal arm (26) member with a telescopically inserted second longitudinal arm member (28). The second arm member (28) is slideable to any one of a plurality of extendable positions and a fastener plate (100) disposed between the first and second members (26, 28) is provided for urging the second member (28) against the first member (26) in friction locking engagement. A plurality of gate lamps (38) are provided having a housing (40) which includes a channel for receiving an upper edge of the crossing arm (24). Screws (50) on both sides of the housing (40) are turned until the housing (40) is secured to the crossing arm (24) in a friction fit. Extensible cables (70) with three-pronged connections connect the gate lamps (38) to circuitry to operate the gate lamps (38) in a predetermined pattern.

Abstract: A railroad train moving along an approach to a grade crossing (or other location of interest) is detected by apparatus that is responsive to the change in effective track impedance caused by the moving shunt. A constant current AC signal is applied to the track adjacent the crossing, and the resulting voltage changed in amplitude and phase is picked off by a receiver on the opposite side of the crossing. Voltage and current information derived from these signals is inputted to a microcomputer which calculates the track impedance and determines whether or not a warning device or devices at the crossing should be activated. Such determination is made on a repetitive basis in accordance with a repeating program loop and stored in memory.

Abstract: A sensor arrangement is disclosed for detecting the presence of an axle of a rail vehicle in a short length of a track. The arrangement includes a bridge coupled to and including resistances of the rail upon which the vehicle travels. This bridge is unbalanced by wheels of an axle shunting resistance of the bridge with the bridge unbalance producing an output indicative of the presence of the axle. Two such arrangements displaced relative to each other will enable detecting the direction of movement of the vehicle. This sensor arrangement contains no electric components on the rail and is insensitive to interference from rail currents and electromagnetic rail brakes.

Abstract: A train approach detector uses frequencies in the audio spectrum to activate grade crossing protection devices in advance of and during the presence of railroad trains at grade crossings. The detector is completely solid state, and includes one transmitter and one receiver each connected to the tracks so that transmitted and received track signals, which are partially pulse modulated for optimum filtering and signal coupling and minimum third harmonic radiation, appear on opposite sides of the crossing. The section of track between the transmitter and receiver is designated as a crossing island and sections of rail outside of the island are known as approaches.

Abstract: A railroad highway crossing warning system including pickup coils for sensing current flowing in the track rails of an approach zone, a circuit for sensing the voltage across the track rails, band-pass filter circuits for filtering the voltage and current derived from the track rails, impedance calculator circuits for calculating the track impedance, phase detector circuits for detecting the phase angle between the voltage and current, a multiplier circuit for linearizing the track impedance by multiplying the track impedance by a function of the phase angle, a data sampler circuit for sampling the linearized track impedance at given periodic intervals, a motion detector and crossing predictor circuit for detecting the motion of a train and for predicting the time of arrival at the crossing by comparing the predicted time of arrival with an advanced warning time, and a logic gate circuit for activating the warning apparatus at the crossing when the predicted time of arrival is less than the advanced warning t

Abstract: A train detection system for protecting a railroad highway crossing having an a.c. transmitter center-feeding voltage signals into the track rails and having a receiver including at least a pair of coils located on opposite sides of the crossing and disposed adjacent the track rails for defining an island zone and for inductively picking up a.c. signals when the island zone is unoccupied and determines the time of arrival of a train at the crossing.

Abstract: A highway crossing warning system for monitoring the motion and predicting the time of arrival of an approaching train at the highway crossing and for detecting the presence of a broken rail in the approach zone by feeding dual frequency signals into the track rails and measuring the track impedances at the two frequencies and the phase angle of the lower of the two frequencies.

Abstract: At a railroad crossing, a single motion detection unit is selectively coupled to an occupied track in such manner that safe, effective and efficient control is obtained over the crossing alarm device. The means for coupling the motion detection unit includes means for terminating the activation of the crossing alarm device when a train stops on the approach track, but short of the actual intersection. Techniques for multiplexing a motion detection unit with plural tracks at the grade crossing or with multiple track circuits on a single track are provided. Safe operation is assured with multiple track occupancy irrespective of the sequence of occupancy and which is the last to remain occupied or if one of the trains stops or reverses direction of motion.

Abstract: A highway crossing warning system includes a motion detector transmitter and receiver respectively coupled to the track rails adjacent the highway crossing for detecting motion of an approaching train. Wrap-around approach sections initiate operation of the highway crossing warning, but once motion is detected, the motion detector can serve to inhibit the highway crossing warning, after a predetermined delay, if motion indication ceases. To increase the effectiveness of the motion detector, the motion detector transmitter impresses a modulated carrier onto the track rails, wherein the modulation is phase locked to the carrier. The receiver, tuned to the carrier frequency, detects the modulation, and then determines from the level of the modulated signal whether or not approaching motion is detected. The transmitter employs solid state circuits switched between saturated and off conditions to prevent circuit component failures from masking approach motion.

Abstract: Generally speaking the present invention contemplates a kit-type railroad crossing signal device having four red, double lens lights attached to prewired arms, a module for flasher control, a battery box, an automatic controlled battery charger, switching control and, a metal conduit and clamps. A standard railroad signal bell can also be supplied.

Abstract: This disclosure relates to a railroad-highway crossing gate and signal arrangement having an elongated aluminum gate arm movable between a vertical clear position and a horizontal traffic blocking position. The elongated aluminum gate arm is attached by a breakaway connector to a gate arm bracket which is connected to one end of a pair of gate arm support members. A pair of adjustable counterweights are securely attached to the other end of the gate arm support members. A power operating mechanism including a permanent magnet d.c. motor and a gear train rotatably drives an output shaft which has its respective ends attached to the pair of gate arm support members for moving the aluminum gate arm between its horizontal and vertical positions. The d.c.

Abstract: A warning device visually enhances the signalling of a dangerous situation such as an approaching train at a railroad crossing. The warning device includes oppositely rotating rims to which light reflecting discs are attached in surrounding relation to hubs fixed to the arms of a frame extending laterally from a vertical support post. Fixed light emitting surfaces are mounted on the hub facing opposite directions.

Abstract: An adjustable adapter bracket for a railroad-highway crossing gate and signal installation for permitting the elongated gate arm to be shifted laterally to avoid interference with overhead obstacles. The adapter bracket is fixedly attached to the ends of a pair of gate supporting arms and includes upper and lower U-shaped strut members each of which is provided with at least two longitudinal rows or lines of apertures. A breakaway gate arm connector including a pair of apertured mounting plates is selectively positioned along the length of the U-shaped strut member and is securely fastened thereto by a plurality of bolts and nuts. A plurality of reinforcing spacer members are positioned between and are bolted to the upper and lower U-shaped strut members to reinforce and strengthen the adapter bracket.

Abstract: A motor controller for use in railway-crossing signal-gate mechanisms is provided herein. The controller is of a cam type which includes a cam assembly having a movable cam insert that cooperates with a cam follower and switch assembly. The switch controls the gate arm raising motor. The cam insert and cam follower are arranged such that when the gate arm approaches the upright position the cam insert slides quickly or snaps to a position, which permits the switch contacts to open quickly, thereby minimizing arcing between the switch contacts. Moreover, with the cam insert in this position, oscillation of the gate arm about the upright position, which is caused by the gate arm striking the arm stops and bouncing back, is minimized.

Abstract: A railway pivotal crossing gate is made with a modular construction to facilitate repair of the gate. The gate modules are preferably of alternating colors along the length of the gate and have exposed parallelogram configurations so the gate has slash markings. Each module includes an elongated body that is preferably injection molded from a translucent plastic with a hollow construction. Male and female ends of each module interfit with ends of adjacent modules to permit self-threading fasteners to interconnect the modules in a detachable manner. Lights are mounted within certain modules so these modules glow and thereby light the gate. Interconnected wire harnesses of the modules are utilized to energize the lights. The unlighted modules preferably mount light reflectors. The gate modules may have hollow rectangular or trapezoidal cross-sections, the latter being useful in conserving the material from which the modules are molded.

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 system for calibrating a receiver in a railroad grade crossing protection system having a transmitter and receiver connected to the rails and a defined approach track section, utilizes the receiver detected motion voltage to determine low ballast resistance. A signal representative of the ballast condition is then utilized in conjunction with the signal representative of train motion to calibrate the receiver for the particular ballast condition.

Abstract: A first transmitter-receiver movement detector system operable at a first frequency detects a train approaching a first grade crossing or other track location in response to train approach speed and distance, and a repeater receiver movement detector device also operable at such first frequency but located at a subsequent grade crossing or location, which is relatively proximate the first, is capable of looking through the first crossing even under unfavorable ballast conditions thereat to detect an approaching train with respect to its speed and distance from the second crossing. The output of the repeater receiver and that of a further transmitter-receiver movement detector system operable at a different frequency from the first are combined in a logic circuit to provide safe, minimum signal down time at the subsequent location.

Abstract: The operating mechanism of a railroad crossing gate employs a variable mechanical advantage connection to transmit force from the drive motor to the gate member to raise and lower the same. The main shaft of the mechanism serves as a mount for the gate member and its counterweights, and an operating arm is fixed to the shaft and extends radially therefrom. A crank is driven by reduction gearing and is connected to the arm by a sliding coupling which reciprocates on the arm longitudinally thereof as the crank rotates. The axis of rotation of the crank is located such that the mechanical advantage is high when the gate member is in either its raised or its lowered position, decreasing to a ratio approaching unity at the midpoint of travel in either direction. Accordingly, the starting load is minimized, the gate member is accelerated once it is in motion, and its speed is then reduced as it nears the end of its travel.

Abstract: A railroad-highway grade-crossing warning system is accomplished by control circuitry for synchronizing the flash rates of incandescent and xenon lamps so as to produce a continuously uniform signal pattern which can be rapidly identified and understood by a motorist.