GWR Route: Banbury to Wolverhampton

Moor Street Station: gwrms2751

Ex-GWR 4-6-0 No 6013 'King Henry VIII' drifts slowly past Moor Street with Bordesley North's distant signal still not indicating its clear. In the foreground between the tracks of both main lines into and out of Snow Hill tunnel are the Automatic Train Control (ATC) ramps which was a safety system designed to bring the train to a stop if the driver passed the signal at danger or did not acknowledge the warning if the signal was at caution. Pioneered by the Great Western Railway in 1906 the GWR system is now better described as an Automatic Warning System (AWS) which more accurately describes the system. AWS was designed to be part of the signalling system in order to warn the driver about the aspect of the next signal. These warnings were normally given 200 yards before the signal. Information about the signal aspect was conveyed electromagnetically to the moving train through equipment fixed in the middle of the track, known as AWS inductors. Each inductor contained a permanent magnet and an electromagnet which 'cancelled' the effect of the permanent magnet. The system is fail-safe because the electromagnet is required to be energised to give the 'clear' indication, the 'warning' indication being given by the permanent magnet alone.

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