Patent GB-1190129-A (GB)
Title: Apparatus and Method for Generating Stopping Profile Signals for the Automatic Operation of Trains
IPC: B61L3/22
Filed: 1968-12-16
Abstract: 1,190,129. Automatic train control. GENERAL SIGNAL CORP. 16 Dec., 1968 [19 Dec., 1967], No. 59677/68. Heading B7N. [Also in Division G3] In an automatic braking control system for stopping trains at stations in accordance with a stopping profile, each train is brought to a halt with its mid-point opposite the mid-point of the station platform by delaying the start of braking by a distance which depends on the amount by which the train length is in excess of the smallest train length. The track 21, 22 at and in approach to the platform 20 is provided with a first transmitter SZM at a standard stopping distance D in advance of point 2 where the head of the smallest length (2 car) train is stopped, a second transmitter PEM at the start of the Station platform, a third transmitter 28 at the end of the platform, a train presence detector 27 and a wheel detector CLM at the mid point of the platform. Control apparatus 37 on the train is provided with a storage unit 50 which is set to half the number of cars in the train above the minimum number. As the train passes marker SZM the signal picked up by coils 35.36 and receiver 40 disappears and the SZM detector 41 provides an output on line 56 which sets a counter 54 to one car length and reduces the count (equal to distance D or 34 car lengths) in counter 47 by 1 car length. The detector also provides an output to enable gate 57 whereby output pulses (140 per car length) are supplied from axle pulse generator 46. When the count in counter 45 has been reduced to zero, zero detector 59 supplies a 'one' output which reduces the count in counter 47 by one, supplies a count of one to a bias counter 48 and an output via AND gate 60 which restores counter 45 to zero. Assuming a 6-car train the count stored in unit 50 is two so that on the next reduction of the count in unit 45 to zero the count in unit 47 is reduced again by one and that in bias counter 48 is increased to two, equal to that in unit 50. Comparator 49 thus supplies an output which cuts off AND gate 62 and supplies an output to gate 67 to commence stopping of the train. The output from counters 45, 47 and 48 is also connected to an A/D converter 51 and combined in operational amplifier 52 to provide a voltage which is a function of distance to go and this when supplied to a profile generator 53 supplies an output voltage VR indicative of the required speed. This is compared in unit 54 with a voltage Va from the axle driven generator 46 which is a function of actual speed to provide an error voltage to the vehicle propulsion and braking apparatus 55. At the time of enabling gate 67 the distance to go is the distance D or 34 car lengths and this is reduced by the count of the distance pulses supplied by the axle pulse generator 46 until the train is brought to a halt. The distance to go is checked as the train passes marker PEM whereby detector 44 on the train is activated to provide an output on line 69 which resets counters 45 and 47 to the distance to go from the platform end to position 2. After the train reaches the mid point C its leading axle is detected by wheel detector 23 which supplies an output which momentarily suppresses transmission by transmitter 28 and this is detected by unit 42 on the train which supplies via line 70 an output which resets counter 45 to one car length and transfers the number of car lengths in counter 48 to counter 47. Thereafter each fourth axle count, i.e. each time a car passes the station mid point a pulse is supplied via transmitter 28 and detected by detector 43 which resets the counter 45 and reduces by one the count in counter 47.