GB920553A - - Google Patents

Abstract

920,553. Electric selective signalling systems. GENERAL RAILWAY SIGNAL CO. April 21, 1961 [April 21, 1960], No. 14503/61. Class 40 (1). [Also in Group XXX] A central traffic control system for the control of unmanned trains operating over a plurality of rail tracks which are divided into sections by inductive markers, comprises trans-receive equipment on each train for co-operation with the markers, which on reception of a marker signal, originates a radio signal to a central office modulated with train identification and location tones, receive equipment at the central office for the reception and storage of the received signal, manual train eontrol setting means at the central office, means for originating a radio signal from the central office modulated with the train identification and location tones and with one or more operational tones determined by the setting of the manual control means and receive means on the train for reception of the central office signal and for controlling the train in accordance with the operational tone or tones. Each inductive marker, e.g. marker 18.2, includes two check in-out coils each tuned to a specific frequency, in this case frequencies B and D, which co-operate with train-carried trans-receive equipment comprising a sweep frequency oscillator and a receiver to energize, via amplifiers fB and fD, tuned to frequencies B and D, relays B and D and their repeater relays BP and DP. Pick-up of relays BP and DP energizes a location relay 18.2 LT which selects a location tone for application with a train identity tone, e.g. tone 104, selected by the position of switch TIS, to a modulator unit associated with a check in-out transmitter operating at frequency f1. The pick-up of relay 18.2 LT also energizes the transmitter which transmits the train identity and location information to a central control office. The central office receiver, Figs. 5A and 5B, includes a number of output circuits FLM each tuned to a particular location tone and a number of circuits tuned to receive the identity tones. In this case circuits FLM 182 and Train 2 East will be energized, resulting in the pick-up of relay 18.2 CIR 104, indicating at the central office that train 104 has passed location 18.2. The reception of the check in-out signal at the office initiates a transmission to the train of a signal modulated by the train location and identity tones (for address purposes) plus one or more train control tones (see Group XXX). Reference has been directed by the Comptroller to Specifccation 880,634.