Abstract: A fuel measuring system of the bubble type is adaptable for use with a plurality of tanks of predetermined differing geometries. The system employs at least two bubbling tubes located at predetermined locations in a tank. A predetermined volume flow of air is made to pass through each tube. Pressure transducers are used to periodically measure the air pressures supplied to the bubbling tubes. Temperature is also periodically sampled, and the pressure and temperature data is used by a microprocessor to make the necessary computations to first determine the averaged normalized air pressure and then the height of the fuel in the tank. In order to correlate the computed value of fuel height with the actual quantity of fuel in the tank, the microprocessor accesses data in a table lookup memory for the particular tank and performs calculations in order to derive the instantaneous volume of fuel in the tank.

Abstract: A gravity operated switching circuit, having particular application in end of train equipment, allows the microprocessor circuit board in the equipment to be turned off. The circuit turns the power off when the equipment is laid on its side after a predetermined time constant, and when the equipment is again mounted in an upright position, the power is turned on after a different predetermined time constant. A modification of the basic circuit requires a reset button to be manually pressed to restore power after the equipment is again mounted in an upright position.

Abstract: An anti-stall motor drive circuit for a very slow running permanent magnet d.c. motor is disclosed. The slow running speed of the motor sometimes allows an insulating film to build up between the brushes and the commutator which causes the stalled condition. The motor (10) is connected in the collector circuit of a drive transistor (Q1) which has a current limiting resistor (R9) connected in its emitter circuit. A stalled condition of the motor (10) is sensed by a lack of output from a tachometer (16) output. The output of the tachometer is full wave rectified by an operational amplifier (22) and diodes (CR1 and CR2). The rectified tachometer voltage is applied to an integrator (24 and C1) having a clamping diode (CR7) connected in its feedback circuit. A zero output from the rectifier allows the integrator output to ramp up to a limiting value determined by the clamping diode.

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.

Abstract: An improved railroad coupler mount is provided for securely mounting railroad signalling and monitoring equipment (10) on the coupler of the last railroad car of a train. The railroad coupler mount includes a banana shape member (30) which extends through a pair of relief holes (22) in the knuckle (12) of the railroad car coupler. The railroad coupler mount has a tightening means (28) for partially withdrawing the banana shaped member and tightly pressing a support leg (20) against the side wall of the coupler to provide a secure mount which is free of rotation problems. The railroad coupler mount is secured with a locking device (26) which serves the dual function of resisting the total withdrawal of the banana shaped member when the railroad coupler mount is tightened as well as preventing the unauthorized removal of the signalling and monitoring equipment. The railroad coupler mount is attached in a position which avoids damage to the signalling and monitoring equipment due to accidental coupling.

Abstract: A marker light using an array (2) of light emitting diodes (12) in combination with lenses (3) provides a light beam of required intensity, shape and color for railroad applications. The light emitting diodes are arranged in various configurations to form the array (2). The lenses may be Fresnel lenses. Control circuitry (C) energizes the light emitting diodes at predetermined or variable flashing rates. Sensing circuitry (222) senses the failure of light emitting diodes in the array and provides an indication of such failure.

Abstract: A battery condition indicator provides an indication of both the charge used and the life remaining in a rechargeable battery. The time of use of the battery between charges is measured to provide an indirect measure of the charge remaining. The total time of service of the battery is measured to provide an indirect measure of the age or life of the battery.

Abstract: A technique for redundantly encoding data for synchronous or asynchronous serial transmission or recording and the correlative technique for decoding the serial bit stream are disclosed. The encoding technique involves making the second data string of a data string pair the complement of the first data string and formatting to the format H.sub.1 Data H.sub.2 Data where H.sub.1 and H.sub.2 are headers wherein at least one bit is the same in corresponding bit positions of the headers. Decoding involves first detecting the headers and then checking to confirm that the data fields are complements. Also disclosed is a technique for extracting bits from the data stream.

Abstract: An improved attaching device is provided for securely mounting railroad signalling and monitoring equipment (10, 12) on the coupler (36) of a railroad car. A package including a supporting frame (22) to which the equipment is fastened by a draw pull (16) rests on the top surface of the coupler. The supporting frame includes a mounting bracket (32) having an integral rod (50) which extends through the flag hole in the coupler knuckle. The end of the rod projects beyond the bottom of the coupler so that it can be secured. In the second embodiment (FIGS. 8 and 9), the rod (111) has bifurcated extensions (116, 118) which serve to strengthen the supporting frame (80). This embodiment also includes shock absorbing elements (108, 110 and 122). In a third embodiment, a post (162) slidably carries a shaft or rod (188) that is retractable into a locking position with the coupler. A crank (176) is used to retract the shaft into a locking position.