30.03.15
Actions of train crew being investigated after Wootton Bassett SPAD
The actions of a train crew that contributed to a SPAD (signal passed at danger) on the approach to Wootton Bassett junction earlier this month are being ‘considered’ by rail investigators.
At 5.25pm on 7 March 2015, train number 1Z67 passed a signal at danger then came to a stand across the junction.
A temporary speed restriction (TSR) was in place on the approach to signal SN45. A temporary AWS (Automatic Warning System) magnet had been placed on the approach to signal SN43 to warn drivers of this TSR.
Preliminary examinations revealed that when the train was approaching signal SN43, it passed over the AWS magnet. This created both an audible and visual warning in the locomotive’s cab.
However, as the driver did not acknowledge this warning within 2.7 seconds, the AWS system on the locomotive automatically applied the train’s brakes. This should have resulted in the train being brought to a stand, and the driver immediately contacting the signaller.
But the Rail Accident Investigation Branch (RAIB) has found evidence that the driver and fireman instead took an action which cancelled the effect of the AWS braking demand after a short period and a reduction in train speed of only about 8mph. What they did also made subsequent AWS or TPWS (Train Protection and Warning System) brake demands ineffective.
Although the AWS warning associated with signal SN43 was acknowledged by the driver, the speed of the train was not then reduced appropriately on the approach to the next signal, SN45, which was at danger.
As train 1Z67 approached signal SN45, the driver fully applied the train’s brakes but by this point there was insufficient distance remaining to bring the train to a stand before it reached the junction beyond SN45. The train subsequently stopped, standing on both the crossovers and the up and down Badminton lines, at around 5.26pm.
So far, RAIB has found no evidence of any malfunction of the signalling, AWS or TPWS equipment involved in the incident.
No injuries, damage or derailment occurred as a result of the SPAD, but RAIB said its investigation will consider the factors that contributed to signal SN45 being passed at danger, including the position of the temporary AWS magnet associated with the TSR.
It is also examining the factors that influenced the actions of the train crew, the adequacy of the safety systems installed on the locomotive and the safety management arrangements.
(Image: c. Network Rail)
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