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Signal Passed At Danger




Signal passed at danger (SPAD), in Railway Terminology , describes an event where a train has run beyond its allocated Signal Block without authority, as indicated by a Lineside Signal showing danger (typically a red 'traffic light'). It is a term primarily used within the British Railway Industry , although can be applied worldwide. Most SPADs occur at low speed where braking distance has been misjudged, and the train can subsequently be stopped within a safety overlap area, either by the engineer or by an automatic application of the Emergency Brake s by a safety system, such as TPWS . In some situations where a signal cannot be seen due to obstruction, sufficient braking may not have been achieved, and the train will continue to run a significant distance beyond the danger light. Such an incident was determined as the main cause of the Ladbroke Grove Rail Crash at a time when TPWS was not in operation.


ACCIDENTS INVOLVING SPADS




REFERENCES

UK Health and Safety Exec , Retrieved 08 March 2006 .