Patent GB-958610-A (GB)
Title: Railway track fullness system
IPC: B61L17/00
Filed: 1961-12-22
Abstract: 958,610. Track fullness detectors. WESTING- HOUSE AIR BRAKE CO. Dec. 22, 1961 [Dec. 27, 1960], No. 45990/61. Heading B7N. An arrangement for determining the fullness of a storage track in a hump type classification yard comprises means for producing a first signal indicative of the number of vehicles counted entering the storage track and means for modifying this signal in response to a second signal indicative of the distance between the entrance end of the storage track and the vehicle nearest thereto. Vehicles passing through track section R1T on route to either storage track section 1T, 2T or 3T operate a wheel trip TRC which applies a pulsed signal via contacts a of relays WS1P, WS2P, which are set in accordance with the destination track section, to that one of the three two-direction impulse actuated motors shown T1RST, T2RST or T3RST, associated with the destined track section. Each motor, e.g. motor T1RST, includes a forward winding W1 a reverse winding W2 and a rotor 1R coupled to the tapping of a potentiometer TF1POT, which at its tapping point provides a signal for retarder control computer apparatus CP indicative of the number of vehicles counted into the track section and to an indicator T1V1 which shows the number of vehicles in the section or the number of available vehicle spaces. The entrance to each section is insulated by joints J and alternating current supplied to each section by transformers, e.g. to section IT by transformer 1TT, develops a voltage across the entrance proportional to the distance between the entrance and the axle of the nearest vehicle in the section to the entrance. This voltage is applied via a selected front contact d of relays 1C, 2C or 3C, a rectifier RC and a differentiator D1F to energize a relay MDR and its repeater relay MDPR if the vehicle is moving above a predetermined speed and also to a servomotor SVM which drives the tapping of a potentiometer SV1POT until the voltage at the tapping equals the applied signal. The voltage at the tapping of a second potentiometer SV2POT, also driven by the servomotor represents the distance between the track entrance and the vehicle. A stepping switch (not shown) operates in turn relays 1C, 2C and 3C (not shown) to compare in turn the signal for each section representing the number of vehicles counted into the section and the signal representing the distance between the entrance and the nearest vehicle in the section. For example, assume relay 1C is operated to compare the signals associated with track section 1T, the voltage developed across the entrance to the section is applied via front contact d relay 1C to the servomotor and the tapping of potentiometer SV2POT is set to supply a voltage proportional to the available distance in the section. After a delay determined by a time delay relay 1TER (not shown) this voltage and that at the tapping of potentiometer TF1POT are applied to relay circuits SUR and ADR and assuming the voltage at the tapping of potentiometer SV2POT is the more positive, relay SUR and its repeater SUPR are energized. Relay SUPR energizes a relay switching circuit including a relay CA (not shown) which is alternately energized and de-energized. A contact c of this relay is connected in series with a front contact b of relay SUPR and a front contact c of relay 1C and provides a pulsed signal to the reverse coil W2 of impulse motor T1RST which rotates the motor and alters the position of the tap of potentiometer TF1POT to bring its voltage into agreement with that supplied by the tapping of SV2POT. If the voltage at the tapping of potentiometer TF1POT is the more positive a similar pulsed signal is applied to the forward winding W1 of the motor. In the event that a vehicle is detected as moving in the track section, the consequential energization of relay MDPR actuates the stepping switch to the next section. Manual means are provided for altering the settings of the tappings on the potentiometers TF1POT &c.