Railway worker warning central unit

摘要

The central unit has a signal receiver (2) for detecting signals at least of an external signal generator which signals the approach of a train. The unit also has at least a computer (4) for analysing the received signals. A non-erasable, static set memory unit (5) is mechanically associated with the computer (4). A modem (8) is controlled by the computer for data transmission to optical and/or acoustic alarm indicators. The signal receiver is arranged to simultaneously receive two pre-programmable signals from the generator. One of the signals act as presence signals to signal the functioning of the generator. The second signal acts as a train detection signal to signal the approach of a rail vehicle. Both signals have different fixed frequencies which are separately analysed in the signal receiver.