Patent GB-964974-A (GB)
Title: Remote control system for railway locomotives or trains
IPC: B61L3/12
Filed: 1960-11-09
Abstract: 964,974. Remotely controlled locomotives. GENERAL RAILWAY SIGNAL CO. Nov. 9, 1960 [Nov. 9, 1959], No. 38565/60. Heading B7N. [Also in Division G3] A remote control system for a locomotive comprises manually controlled means at a central office for radiating coded electric signals and receiving means on the locomotive for detecting the radiated signals and for effecting the appropriate controls. In the system described a locomotive and five " dump-oars " are remotely controlled. The dump-cars DC1- DC5, Fig. 1, are loaded at an excavation site and when full they are drawn, under remote control, to a hopper H, into which they individually discharge their contents. The control system, Fig. 2, provides two speeds in .both forward and reverse directions. It also provides for the selection, by a switch DC, of any one of the five dump-cars, which when selected, dumps its contents upon depression of a dump execute button DE. All controls are transmitted from the central office to the locomotive by means of six frequencies f1 to f6 modulated on a carrier frequency. Speed control of the locomotive is effected in two stages by frequencies f1 to f3, selection of a particular dump-car is effected by transmitting a combination of the three frequencies f4 to f6, and the dump execute control (effective only after a particular dumpcar has been selected) is effected by frequency f2. Central office, Figs. 4A, 4B.-Upon moving the train control switch TC, Figs. 2 and 4A, from its central " stop " position, at which position only the carrier frequency is transmitted, a relay CK1, Fig. 4B, is energized and a relay IS is de-energized which initiates a check operation, which comprises the transmission of all six frequencies simultaneously for a short period, followed by the transmission of nothing for a short period. The relays IS and CK1 together cause the transmission of all the frequencies, and the relay CK1, by de-energizing a relay CK2, which is slow to drop-out, also causes the transmission of nothing. One of relays R or F is then energized to effect reverse or forward control, which causes the transmission of frequency f3 or f1, respectively, and this is followed by the energization of a slowspeed relay SS, which adds frequency f2 to the frequency already being transmitted, or the energization of a fast-speed relay FS which also causes relay SS to pick-up and which results in the transmission of all three frequencies f1 to f3. Selection of a dump-car is effected, with the train control switch TC set to zero, by the dump-control switch DC, Fig. 4A, which transmits a different combination of the three frequencies f4 to f6 for each of its five positions, and the actual dumping is initiated by depression of the dump execute button DE which causes the transmission of frequency f2. Locomotive, Figs. 5A, 5B, 5C.-Each of the six frequencies f1 to f6 when received by the locomotive energizes a corresponding relay 1L, 1M, . . . 2H, Fig. 5A, via appropriate filters. When all six frequencies are received simultaneously, during the check operation, all six relays 1L, 1M, . . . 2H pick-up together with a relay CR which responds to the carrier signal. This causes a capacitor 43 to charge via seriesconnected contacts 44, 45, . . . 50 When this is followed by a brief interval of " silence " all these relays 1L, 1M, . . . 2H and CR drop-out whereupon a check relay CK is energized from the changed capacitor 43 via series connected contacts 52, 53, . . . 58. The check relay is sufficiently sluggish to stay up until the carrier signal is restored whereupon carrier relay CR picks-up and establishes a hold circuit for it. The interval of " silence " which concludes the test period, is followed by the reception of either frequency f1 or f3 which causes, via contacts 112, 113, 162, Fig. 5A, either a forward relay F1, Fig. 5B, or a reverse relay R1 to be energized. To the selected frequency (f1 or f3) is added either f 2  by itself, which causes, via a contact 118, a slow speed relay SS1 to be energized or f2 together with the unselected frequency-resulting in all three frequencies f1, f2 and f3-which causes the slow speed relay SS1 to pick-up, as before, and also causes a fast speed relay FS1 to pick-up, via series connected contacts 44, 45, 46. This, in turn, causes the locomotive to be driven at the slow or fast speed (see below). Once the locomotive has been driven to the desired position and stopped, selection of one of the five dump-cars is effected by a combination of three frequencies f4, f5 and f6 which when received set up a route from a contact 206, Fig. 5A, to the appropriate one of five dumping valves 1CD, 2CD, . . . 5CD. The actual dumping is then initiated by the reception of frequency f2 (by depression of the dump execute button at the control station). Speed control, Figs. 5B, 5C.-The locomotive throttle control apparatus, Fig. 5C, is of known type and is controlled by four solenoids T1V, T2V, T3V, T4V. These solenoids in turn are controlled by a multi-position stepping switch SW, Fig. 5B, forward (or up) stepping of the switch energizing the solenoids in the correct sequence to open progressively the locomotive throttle, and backward (or down) stepping of the switch progressively closing the throttle. Up or down stepping of the switch is effected respectively by relays US and DS which, when energized, oscillate continuously. These relays are so controlled that the switch is stepped up or down until the locomotive speed has the desired selected value. The selected speed can be either slow, that is in the range 4-5 m.p.h., or fast, that is in the range 10-12 m.p.h. If the slow speed is selected then the control circuit first compares the locomotive speed with 4 m.p.h. until 4 m.p.h. is exceeded, then it compares the locomotive speed alternately with 4 m.p.h. and 5 m.p.h., and if the locomotive speed continues to rise the control circuit compares it with 5 m.p.h. Thus when the locomotive speed is in the desired range it is compared alternately with 4 m.p.h. and 5 m.p.h., and when it is outside the desired range it is compared either with 4 m.p.h. or with 5 m.p.h. whichever is appropriate. This control is effected by a circuit comprising a frequency generator FG driven by the locomotive wheels, two filters which will respectively block frequencies below those which correspond to speeds of 4 or 5 m.p.h. and 10 or 12 m.p.h. depending upon whether or not two capacitors 23, 24 are shunted by a relay C, an oscillator generating a frequency higher than 12 m.p.h., an amplifier 27 and relay D1 which respond to the output from the filters, and a relay GR which selects the desired speed range by selecting one of the two filters. The operation, assuming for example that the slow speed is selected, is as follows. With the locomotive at rest the signal from the oscillator passes through the 4-5 m.p.h. filter and picks up DP via D1. DP opens contacts 145a which turn off the oscillator. Thus with the locomotive at rest relay DP is continually oscillating. This causes a relay C to be held up, which, in turn, keeps CP up. When a " slow-speed " control signal is received by the locomotive it energizes a relay SS1, Fig. 5B, which, in turn, energizes selfinterrupting relay US and the multi-position switch starts stepping upwards thereby progressively opening the locomotive throttle. When the locomotive speed rises to above 4 m.p.h. but remains below 5 m.p.h. the basic oscillatory loop (osc., filter, relay DP) stops oscillating because the signal from the frequency generator FG passes through the filter continuously. However, once DP stops oscillating relay C falls out which removes the shunt across capacitor 23 and raises the setting of the filter to 5 m.p.h. Thus with the locomotive speed between 4 and 5 m.p.h. the basic oscillatory loop is blocked but a second loop including relay C becomes operative. While C is oscillating, CP, which is slow-to-release, stays up, and a further relay OS, also slow-to-release, pioks-up. This causes the de-energization of US and no further stepping of the multi-position switch occurs. Providing the locomotive speed remains in the range 4-5 m.p.h. the condition, with relay C oscillating and relays CP and OS up, continues. If, however, the speed rises above 5 m.p.h. then relay C stops oscillating and falls out. This causes both CP and OS to fall out, which, in turn, causes the energization of self-interrupting relay DS and the consequential down stepping of the multi-position switch, and hence the locomotive throttle is progressively closed. When the locomotive speed falls to 4-5 m.p.h. range relay C recommences oscillating as above.