Abstract: A brake adjustment monitoring system, including a sensor having a movable actuator for mounting in or on a brake service chamber and circuitry which responds to the actuator's position to generate a display indicating whether the brake is correctly adjusted (after actuation of the brake). In preferred embodiments mounted in a motor vehicle having several brake assemblies each including a service chamber, a sensor is mounted in each service chamber, and a display panel mounted to the dashboard indicates the status of each brake assembly or each pair of the brake assemblies. Preferably, each sensor is designed for use with an air brake assembly including a service chamber, a push rod having one end outside the chamber and another end in the chamber, and a slack adjuster connected to the push rod's outer end.

Abstract: An automated terminal test system for performing a terminal test of brake equipment on a train includes a test control box connected to a head of train locomotive and accessible from outside of such locomotive. Linked to such brake equipment, the test control box has a control for activating the test control box, applying and releasing the brakes, and charging and venting such brake pipe. The system also includes an end of train transceiver device connected to such brake pipe on a last railcar of such train. The end of train transceiver device monitors pressure within such brake pipe on such last railcar, senses movement of such last railcar, and communicates signals representative of such pressure monitored and such movement sensed. The system further includes a head of train transceiver device linked to such brake equipment and connected to such brake pipe on such locomotive.

Abstract: Method and apparatus for monitoring brake performance and updating information relating to brake performance while a train is in motion. A computer on the train is provided with inputs for grade information, axle speed, brakepipe pressure, and locomotive tractive effort. During brake applications when the train is in motion, calculations are made by the computer to update parameters which relate to braking performance, and to generate signals representing those parameters.

Abstract: A system for determining a residual life of a friction clutch is constructed so that the loaded condition of the clutch is determined in accordance with detected differential revolution, control oil pressure, oil temperature, and loading time, with which the residual life of the friction clutch is calculated.

Abstract: An integrated highly automated vehicle analysis system employs a technician terminal for displaying a plurality of inspection screens, and for entering inspection results. The technician terminal generates an inspection report after the inspection results have been input. A point-of-sale terminal is used to generate a cost estimate report in response to the generation of the inspection report and also generates an invoice report. The system includes a plurality of databases, including an inspection guideline database, a specifications database (containing vehicle specifications), a customer/inspection database (containing prior inspection records), and a parts catalog database (containing part numbers and part costs).

Abstract: An operating variable detected by at least two control units for actuating the brakes is distributed to a central control unit which identifies an error state in the area of the control unit in question when the operating variable in question deviates unacceptably from a reference value.

Abstract: For use with control valves having test ports via which various pressures may be accessed in performing an automatic single car brake test, there is provided a test plate via which such control valves may be conditioned to obtain faster charging of the brake equipment when performing the brake test with a manual single car tester. The test plate interconnects the test ports such that the test pressure supplied to the car brake pipe charges the brake equipment in by-pass of the charging choke in the control valve.

Abstract: Measuring the force of a spring (28) in a spring brake actuator (10) comprising a housing (14) having an end wall (46), a spring plate (30) within the housing (14), the spring (28) being disposed between the spring plate (30) and the housing end wall (46) and a caging bolt (34) extending from the spring plate (30) through the housing end wall (46) and having a nut (44) thereon with a gauge between the caging bolt nut (44) and the housing (14). The gauge comprises a pressure-responsive element which detects the compressive force between the nut (44) and the housing (14) and generates a signal responsive thereto. An indicator (86) is coupled to the pressure-responsive element and visually displays the force on the spring (28) as a function of the compressive force signal. An embodiment of the gauge (50) comprises a body (52) having a bore (58), a piston (64) received within the bore (58) defining a chamber (74) between the piston (64) and the body (52) and a fluid (72) in the chamber (74).

Abstract: A pneumatic receptacle adapted to receive a pneumatic connector head of a test device is mounted in a universal location remote from the brake control valve of a railroad freight car. The remotely mounted receptacle may be located on the railroad car body, for example, and is communicated with access ports associated with the control valve via hoses or conduits. In locating the receptacle on the car body, hook-up of the test device can be accomplished conveniently and in a safe manner by railroad personnel in the course of conducting a single car test to check the condition of the car brakes, regardless of the control valve location.

Abstract: A method checks a vehicle brake system rapidly and reproducibly to measure the correlation between the brake pedal travel and the retardation produced. A test-bed routine is called up in the control unit. During the operation of the test-bed routine, the functioning of the brake system is checked. For this purpose, a pressure difference is produced in the vacuum brake booster. The brake booster pressure difference produces a brake pressure in the brake master cylinder, and a pedal travel corresponding to this brake pressure simultaneously arises. The retardation can either be measured at the rollers of the test bed or is derived from continuously measured wheel speed values. A retardation value can be determined for each wheel as can a correlation between the pedal travel and the retardation from the measured values in the presence of different brake booster pressure difference. The process can average the values measured at the individual wheels.

Abstract: A vehicle yaw rate control method comprising the steps of: first estimating vehicle yaw rate responsive to a first set of criteria; second estimating vehicle yaw rate responsive to a second set of criteria, wherein the first set of criteria includes a first vehicle condition not included in the second set of criteria and wherein the second set of criteria includes a second vehicle condition not included in the first set of criteria; measuring vehicle yaw rate using a yaw rate sensor; and indicating a reverse travel condition if both of the first and second estimates have signs opposite to a sign of the measured vehicle yaw rate.

Abstract: A method and apparatus for non-destructively proof-testing the integrity of the bond between an integrally-molded disc brake pad assembly metallic backing plate element and its adhered molded friction material pad element advantageously tests the bond by tensile stressing rather than by conventional shear stressing.

Abstract: A process to determine the response pressure of a brake in a braking system of a vehicle comprises: measuring the existing vehicle deceleration of the vehicle to determine a value of ground-vehicle deceleration, supplying a test pressure to the brake, measuring the deceleration of the vehicle after the test pressure has been supplied to the brake to determine a value of vehicle test deceleration, and comparing the value of ground-vehicle deceleration and the value of vehicle test deceleration. If the value of vehicle test deceleration is greater than the value of ground-vehicle deceleration by more than a predetermined tolerance value, the steps of the process are repeated with a reduced test pressure until the difference between the values of ground-vehicle deceleration and vehicle test deceleration is no more than the predetermined tolerance value.

Abstract: A portable, hand held device for testing the air brakes of a tractor trailer type truck. The device is generally comprised of an elongated body having a cavity bored therein which extends perpendicularly to the longitudinal axis of the body, and an inlet and outlet attached to opposite ends thereof. A valve assembly consisting of a series of co-linearly mounted, axially displacable springs and plungers are operatively positioned within the bore, and effectively open or close the fluid communication between the inlet and outlet. A first hose extends between a compressed air tank and the inlet, and a second hose extends between the outlet and the glad hand of the truck. A lever is pivotally attached to the body for effecting operation of the valve assembly, and thus may be selectively moved to effect the flow of compressed air from the compressed air tank to the glad hand.

Abstract: An integrated highly automated vehicle analysis system employs a technician terminal for displaying a plurality of inspection screens, and for entering inspection results. The technician terminal generates an inspection report after the inspection results have been input. A point-of-sale terminal is used to generate a cost estimate report in response to the generation of the inspection report and also generates an invoice report. The system includes a plurality of databases, including an inspection guideline database, a specifications database (containing vehicle specifications), a customer/inspection database (containing prior inspection records), and a parts catalog database (containing part numbers and part costs).

Abstract: A brake lining temperature and wear sensor having a plurality of serially connected wire loops and a resistive temperature sensor having a lower range of resistance than any one resistor mounted in a cavity formed in the brake lining where a plurality of resistors are connected one to each wire loop to be sequentially connected to a sensor circuit as the brake lining wears and breaks each wire loop. A control unit provides an electrical current to the sensor circuit and monitors the electrical potential across the plurality of wire loops and the resistive temperature sensor and then generating an output signal representing the temperature and wear of the brake lining. In an alternate embodiment, a capacitor is connected across the plurality of wire loops and a resistive temperature sensor with a large range of resistance is used to monitor the brake lining temperature.

Abstract: The invention is directed to a pressure monitoring system for monitoring a hydraulic pressure which is supplied from a fluid pump and accumulated in an accumulator. The pressure monitoring system includes an electric motor which drives the fluid pump to supply the hydraulic pressure in substantially linear proportion to a current fed to the motor, a current detection device which detects the current fed to the motor, and a pressure estimation device which estimates the hydraulic pressure accumulated in the accumulator in response to the current detected by the current detection device. A malfunction detection device may be provided for detecting a malfunction on the basis of the output of the pressure estimation device.

Abstract: A brake pad wear probe contains a plurality of terminals turned or bent into a U-shape with their tip positions offset from each other. The terminals are cut in stages according to the wear development degree of the brake pad. The terminals define energization routes to electro-magnetic coils at relays, and the broken line state of the terminal can be detected at the respective relay by detection of a break in its corresponding energization route. As a result, electro-magnetic switches work in response to the wear development degree, turning on predetermined indicator lamps of a display to inform a driver of the brake wear condition.

Abstract: A railway vehicle brake system tester for performing at least one test procedure on an electronically controlled railway vehicle brake system disposed on a railway vehicle without requiring removal of such electronically controlled brake system from such railway vehicle which includes a mounting member for mounting a number of predetermined components of such railway brake system tester thereon. A microprocessor unit is disposed on such mounting member and is connected to receive and communicate information required for performing such at least one test procedure. Another device is disposed on such mounting member and is connected for receiving preselected outputs from such brake system and is connected to communicate such preselected outputs to such microprocessor and is connected to receive preselected inputs from the microprocessor and is connected to communicate such preselected inputs to such brake system.

Abstract: A test unit is provided for operatively testing CV driveaxles. The test unit has a drive spindle connected to a motor, and a pivotable brake spindle connected to a brake. An axle under test is connected with spindle adaptors to the drive and brake spindles. During a test, the axle under test is rotated by the motor, the brake is engaged to load the axle, and the brake spindle is pivoted to flex at least the outboard CV joints. The test unit is easily adaptable for testing different axles by using spindle adaptors. An accelerometer on the bearing block of the brake spindle detects vibration generated by the axle under test.

Abstract: A test connector for connecting an air brake test device to access ports of an air brake control valve device where such access ports are normally closed by check valves. A plurality of actuator devices corresponding in number to the access ports are provided in the test connector to unseat the check valves and conduct test air to the test device via central passages in the actuators. The actuators are piston operated in response to a pilot pressure received from a source of compressed air remote from the connector.

Abstract: A real-time simulation system for testing an ABS controller. The simulation system receives car dynamic data from a computer and transmits the car dynamic data to the ABS controller through a controller conversion circuit. The simulation system then receives control signals from the ABS controller and feeds the control signals back to the computer through the controller conversion circuit so as to calculate, analyze, and display results on the monitor of the computer.

Abstract: A brake performance monitor has a first sensor 12 for detecting movement of a brake device to apply the brake, and a second sensor 14 for detecting a predetermined force necessary to apply the brake in normal operating conditions. If the braking force deteriorates, the brake movement is detected before the predetermined force is reached, and an output device 10 signals the fault, for example by halting the machinery 4 being braked.

Abstract: A process and apparatus for measuring the wear of a multiple disk brake while a wheel hub is rotationless. A measuring instrument is provided having a screw-like component and a spindle. A plug element located in a predetermined bore of the wheel hub is replaced with the screw-like component. The brakes are actuated, the spindle is moved while the brakes are actuated until the spindle comes into contact with a supporting disk that axially supports the multiple disks. The distance the spindle was moved is ascertained to form a first measured value. The brakes are then released, and the spindle is moved again, until the spindle again comes into contact with the supporting disk. The distance the spindle was moved is ascertained to form a second measured value. The difference between the first measured value and the second measured value is determined to ascertain a piston stroke, and the wear of the multiple disk brakes is ascertained from the piston stroke.

Abstract: A vehicle testing device and method are provided whereby a mechanic can easily test the pneumatic brake systems of a tractor-trailer. The device is used by inputting into the device the electrical and pneumatic outputs of a tractor and by outputting electrical and pneumatic transmissions from the device into a trailer. The device accepts input from a tractor and produces output to a trailer for testing purposes. The testing device is compact and portable and affords a mechanic a convenient tool for efficiently carrying out the necessary safety tests on both the tractor and trailer which may be physically connected or disconnected at the time the testing occurs.

Abstract: A remote system (10)/method for testing vehicle brake or brake system performance of vehicles (30) driving past a testing module (36) adjacent a test roadway (28A) is provided. Preferably, the system/method is associated with a typical highway weight station (14-22) and includes a brake testing area (28) located in series between the usual weight scales (18) and a ramp (22) back onto a highway.

Abstract: A roller brake dynamometer includes shuttle wheels which engage the dynamometer rollers and are movable between raised and lowered ground engaging positions. The shuttle wheels may be rotated in the same or opposite directions to move the dynamometer forwardly, rearwardly or turn it about its own axis. A dynamometer transport trailer includes an endless conveyor chain running the length of the center of the tiltable trailer bed which includes a tongue engagable with the dynamometer frame for pulling the dynamometer on to and off of the trailer bed.

Abstract: A motor trouble detection device detects trouble in a motor used in an anti-skid brake control system for returning the brake fluid to the reservoir tank. The trouble detection is based on the counter electromotive force generated by the motor which is turned off after driving for a predetermined period. The device includes a first detector for judging whether the counter electromotive force is smaller than a predetermined voltage and a second detector for judging whether the motor is in trouble based upon the first detector.

Abstract: A brake monitoring and warning system is intended for use on a motor vehicle (110), and more particularly is intended for use on tractor-trailer combinations. The vehicle includes plural, powered brakes. Each brake includes a brake activation arm (18) and a mechanism (16) for shifting the brake activation arm between a brake-off position and a brake-applied position, such as an air-driven cylinder. The monitoring and warning system includes a sensor (26) which is connected to the brake-activation arm (18) and monitors the position of the brake-activation arm. The sensor generates and transmits a brake condition signal which is representative of a safety condition of the brake associated with a particular brake activation arm. A logic mechanism is connected to the sensors and receives and interprets the brake condition signal. Visual (160, 162) and auditory (164) warning devices are connected to the logic mechanisms for warning the vehicle operator of the safety condition of the brakes on the vehicle.

Abstract: A vehicle testing device and method are provided whereby a mechanic can easily test the pneumatic brake system of a tractor, converter dolly and trailer. In addition, electrical circuitry is supplied to allow the mechanic to check the electrical circuits from the tractor to the trailer which supply power for the turn signals, brake lights, clearance lights, auxiliary lights and turn signals. The testing device is compact and portable and affords a mechanic a convenient tool for efficiently carrying out the necessary safety tests on both the tractor and trailer which may be disconnected at the time the testing occurs.

Abstract: A production functional test for hydraulic brake control and traction control units which utilizes compressed air as a test medium. Compressed air is applied to an external port of a hydraulic brake or traction control unit which includes valves, accumulators and a positive displacement pump driven by an electric motor connected by internal passageways. The air pressure at another external port is monitored while the various components are exercised according to a test sequence. The monitored pressure must be within predetermined limits at various points of the test to demonstrate that the brake control unit is functioning properly. Air flow rates and pump motor current are also measured at specific points in the test. The test method can identify incorrectly sized and installed components.

Abstract: An abrasion evaluation test method is applicable to a case where a rotating disk and a friction member to be brought into sliding contact with the disk contact and abrade each other even while a brake is not applied due to vibrations and mounting errors. The disk is an actual disk, and the friction member is a test piece which is smaller than the actual friction member. The test piece is pressed against a frictional surface of the disk at a predetermined position, thereof. The abrasion of the disk is measured with respect to a portion of the frictional surface that is out of contact with the test piece, while the abrasion of the friction member is obtained from the difference in thickness of the test piece before and after testing.

Abstract: A test for an electronically controlled braking system, such as an adaptive braking system, is made to assure that the solenoids of each of the modulators are properly wired. According to the test, each modulator is tested in sequence. The exhaust solenoid of a modulator is actuated for 10 milliseconds, and the hold solenoid is then actuated for 30 milliseconds. If the modulator has been miswired, the exhaust solenoid will have been actuated for 30 milliseconds, thus generating a much louder "popping" sound than that generated by the other modulators will be immediately noticed and corrected.

Abstract: A plate brake tester for testing the adequacy of the brakes of a vehicle, particularly suited for testing the brakes of multi-axle vehicles, includes weight bearing plates suitably sized to receive thereon wheel/tire assemblies of a vehicle as the vehicle is driven over the plates. The plates have sensors associated therewith for sensing not only the brake force applied by each wheel/tire assembly, but also for directly sensing the dynamic weight of the wheel/tire assembly on each plate during braking. The adequacy of the brakes is determined from the brake force and the directly sensed dynamic weight. At least some of the sensors are preferably dual axis load cells, each dual axis load cell having one output representing vertical force applied to that plate and having a second output representing horizontal force applied to that plate, the horizontal force being the braking force from the wheel/tire assembly disposed on that plate.

Abstract: A hinge assembly for a manual or automatic air brake valve test fixture that includes a secondary test plate to which a valve device to be tested is mounted from a front load position and then rotated to its usual side location for clamping to the primary test plate, thereby relieving the tester of physical strain encountered heretofore in mounting the valve in a side load position. The hinge assembly is spring-loaded to obtain even, face-to-face engagement of the mating surfaces of the primary and secondary test plates and thereby assure the integrity of the pressure seal therebetween.

Abstract: A testing and bleeding apparatus incorporates an adapter rack, an adapter cable and a bleed cable harness for connecting the main unit of the apparatus to an automatic braking system. An adapter rack hold down assembly is used to secure the apparatus in order to allow in flight testing of the ABS. The apparatus incorporates bypass switch panels, a test switch and indicator light panels to test the circuitry and components of the ABS. The apparatus also incorporates a voltmeter, a meter select switch to tap into selected ABS circuits, a test lead and sets of test jacks to test each individual ABS wire as well as other selected components of the ABS.

Abstract: A comprehensive brake testing method and device is provided which is specific for the vehicle in question; wherein the manufacture's brake specifications for each vehicle model are stored on a data bank linked with the device, and the make, model, and year of the vehicle to be tested is input into the device which device steps the operator through a series of visual and measured tests with the results of such tests being entered into the device either manually via a keyboard or automatically from computer interfaced torque wrenches hydrometers and/or micrometers. The results are compared to the manufacture specifications and additional testing or repair is recommended by the device as required.

Abstract: A pneumatic or hydraulic pressure sensor is connected in parallel with the vehicle braking system and the sensor is connected to a computer system which periodically samples the sensor output. Other sensors can be used to detect other quantities such as engine speed, vehicle speed, wheel rotation or transmission speed, and other brake units and their outputs can also be periodically sampled. Under control of the computer, the samples are stored on a magnetic disk. The computer can then be instructed to interrogate the samples stored on the disk to produce charts of various quantities versus time which objectively indicate driver performance. The device can also be used to synchronize individual brake units in a multiple brake vehicle by simultaneously displaying the brake pressures in each brake unit, thereby enabling the relative application timing of the brake units to be measured.

Abstract: A compound or multi-function tool facilitates manually moving of the brake rod of a motorized land vehicle, and provides a dimensional scale integrally therewith by which the distance of travel of the brake rod between its brake-off and brake-on positions is visually observed and measured.

Abstract: The frictional properties test mechanism (10) comprises a shaft dynamometer (12) connected with a wheel element (14) that is coupled with a braking mechanism (16) for the wheel element (14). The braking mechanism comprises a single rotor (25)/double stator (27) disc brake whose torque tube (29) is attached to a piston housing (40) and torque load cell (54). The piston housing (40), torque armature end plate (41), and torque load cell (54) are mounted by way of bearings (95) within a stationary framework (100), and connected with an oscillatory motion mechanism (18). Located adjacent the stationary framework (100) and connected by arms (24) to the end plate (41) and torque load cell (54) is a pair of spring mechanisms (20) and a pair of hydraulic cylinders (22), which are part of the oscillatory motion mechanism (18). A control and display console (121) operates the dynamometer (12) in order to effect rotary motion of the wheel element (14) and operation of the braking mechanism (16).

Abstract: A method is disclosed for monitoring braking torque capability of a brake used for selectively braking a shaft of an exemplary control rod drive. The method includes the steps of rotating the shaft, engaging the brake, torsionally restraining the brake for allowing rotation of the brake up to a predetermined maximum angle, and monitoring the angle for monitoring braking torque capability of the brake. A preferred embodiment of a brake assembly for carrying out the method includes a stationary base, a bearing mounted to the base, a brake mounted to the bearing for rotation relative to the base, means for torsionally restraining the brake for allowing rotation of the brake up to the predetermined maximum angle, and means for monitoring the angle.

Abstract: A conversion kit for modifying a single car test device regulator valve, such as to provide an adjustable maximum test operating pressure in one position of the regulator valve handle, and a reduced operating test pressure in another handle position of the regulator valve that is less than the maximum test operating pressure by a predetermined amount, in order to satisfy the requirements of a new test procedure mandated by the Association of American Railroads for more accurately utilizing the results of a leakage test as an indication of the operating condition of the car control valve during the single car test.

Abstract: A vehicle anti-lock brake system having a main microprocessor and fail-safe microprocessor of a different type from the main microprocessor, and a device interconnecting the main and fail-safe microprocessors and the remainder of the vehicle braking system so that the fail-safe microprocessor can disable the brake release system independently of the main microprocessor.

Abstract: An aircraft brake tester includes pressure transducers to detect pressure levels in each of a plurality of hydraulic lines connected to each of a plurality of aircraft disc brake cylinders, respectively. Each aircraft disc brake includes a set of cylinders, each connected to one of a set of hydraulic lines. Each respective hydraulic line exerts a hydraulic pressure to a respective cylinder engaged with the hydraulic line potentially resulting in different cylinders on the same aircraft brake receiving different hydraulic pressures. The pressure transducers convert the detected pressure levels into analog signals and output the analog signals to a processor. The processor digitizes, references and calibrates the analog signals into actual pressure values and simultaneously displays the actual pressure values.

Abstract: A set of wheel speed sensors forming parts of an anti-lock brake control system are tested for proper connection and operation when mounted on a motor vehicle. A check signal is first input to a sensor check terminal connected to a control circuit included in the brake control system, thereby causing the control circuit to light a warning lamp. Then the wheels of the vehicle are successively rotated in a predefined sequence and at a speed corresponding to the lowest vehicle speed at which the brake control system must be active. If all the wheel speed sensors deliver there outputs to the control circuit in the predetermined sequence, the warning lamp goes out to indicate proper functioning and proper connection of the sensors. The warning lamp remains illuminated if one or more of the wheel speed signals are not into to the control circuit or if the wheel speed signals are received by the control circuit in other than the predetermined sequence.

Abstract: A braking control apparatus for use in a motor vehicle having at least one wheel comprising a master cylinder for generating a hydraulic pressure in response to a braking operation of a vehicle driver, an accumulator for accumulating a hydraulic pressure and at least one wheel braking cylinder for braking the wheel in accordance with a hydraulic pressure supplied thereinto. A passage system is provided so that the wheel braking cylinder is communicated therethrough with the master cylinder and the accumulator. In the passage system are provided first and second change-over valves for cutting off the pressure from the master cylinder, cutting off the pressure from the accumulator and a third control valve disposed between the wheel braking cylinder and the master cylinder or the accumulator for establishing and cutting off the communication therebetween.

Abstract: An anti-lock hydraulic brake system which includes a brake pressure generator composed of a master cylinder, a brake power booster inserted upstream thereof and a pressure modulator interposed between the master cylinder and the brake power booster. A resetting unit is formed by supplementing the pressure modulator with a valve assembly which connects a resetting chamber of the pressure modulator to either a pressure-compensating reservoir or an auxiliary-pressure source. The braking pressure in the wheel brakes is controlled, according to a time-multiplex method, by wheel valves inserted into the pressure-fluid conduits and by the pressure modulator. In order to check the operability of the brake and of the anti-lock control system, a pressure switch is connected to the pressure modulator and a test circuit is provided which, at predetermined points of time, initiates a test cycle, actuates the valves and compares the valves' operation with the reaction of the pressure switch.

Abstract: An abnormality detecting device for detecting a breakage in wiring of a rotation sensor. When the rotating acceleration calculated based on signals from the rotation sensor is greater than a predetermined acceleration value and the rotating speed calculated based on signals from the rotation sensor is zero, a detection signal is put on a wire connected to the rotation sensor. A change in the level of the detection signal is checked for determining whether the rotation sensor is abnormal, i.e., whether there is a breakage in the rotation sensor.

Abstract: A method and apparatus for testing motor vehicle anti-skid braking systems is disclosed which is particularly well suited for production line verification of the anti-skid braking system integrity. The method comprises monitoring the operation of a pressure generating device which operates intermittently to generate brake actuating pressure independently of application of the vehicle brake pedal while simultaneously and cyclically applying a predetermined operating force to the vehicle brake pedal and measuring the distance of travel thereof for each successive operation. The first phase of the test procedure enables verification of the operation of the pressure generating device and associated controls therefor whereas the second phase of the test sequence verifies the absence of fluid or pressure leakage in another portion of the braking system.

Abstract: An improved automatic train-line air brake pressure monitoring system includes circuits that emulate an automatic brake valve and cause an automatic brake manifold release whenever a four psi increase in pressure is sensed. The system includes a pressure sensor amplifier (10) which provides a signal proportional to the sensed pressure in a brake pipe. This signal is tracked by a peak hold circuit (12) that stores the peak value of the signal. The output of the sensor amplifier is subtracted from the output of the peak hold circuit in a subtractor (14) to provide a difference signal. The difference signal is tracked by a reduction hold circuit (22) which stores the minimum value of the difference output from the subtractor. An increase in measured pressure from the stored minimum value is compared in a comparator (24) with a reference value representing the four psi level, and when the increased pressure exceeds the reference value, a system reset is generated.