06 July 2023
"None of the engineered systems provided automatically applied the train’s brakes", study finds.
RAIB has released its report on a buffer stop collision at Enfield Town station, on October 12, 2021. At 08:21 on Tuesday October 12, 2021, an Arriva Rail London (ARL) train hit the buffer stop at Enfield Town station in North London at 7.7 mph (12 km/h). The train struck the buffer stop, which was damaged in the collision, and rode up on it, coming to a rest with its leading wheels about 800 mm above the rails. No serious injuries resulted from the accident.
The train had been travelling at 10 mph (16 km/h) when it was 69 metres from the buffer stop. After briefly applying the brakes, the driver made no further control actions for just over seven seconds, until they made an emergency brake application just before the train hit the buffer stop. This occurred too late to prevent the collision. The accident occurred because the driver of the train did not apply the brakes in time, as a result of him losing awareness of the driving task. The loss of awareness was probably a result of him being significantly fatigued at the time. Post-accident drug and alcohol tests of the driver also yielded a positive result for a recreational drug.
The driver had not reported his fatigue to his employer, who in turn had not identified his fatigue when he signed on duty, or that his personal circumstances made him vulnerable to fatigue. There was also a potential conflict between his employer’s processes for ensuring that staff attended for duty and for managing levels of staff fatigue. None of the engineered systems provided automatically applied the train’s brakes, as the conditions for their intervention were not met. In particular, the Train Protection and Warning System did not activate because the train was travelling below the speed at which the system would be triggered on approach to the buffer stop. This system was installed in compliance with the relevant standards but did not protect against the conditions leading to this accident.
RAIB has made two recommendations. The first is addressed to ARL and relates to encouraging staff to report fatigue that could affect their ability to do their jobs safely. The second, addressed to Network Rail in conjunction with RSSB, seeks to improve the risk assessment process for collisions with buffer stops at terminal platforms.
RAIB also identified three learning points. The first reminds Network Rail and train companies that engineered safeguards do not protect against all events, and that operational controls may also be required to manage risk. The second reminds train staff of the importance of reporting fatigue when it affects their ability to work safely. The third reminds staff of the need to comply with their employer’s drug and alcohol policies.