RAIB urges improvements to cut risks of buffer stop collisions

Merseyrail and Network Rail should improve the way they assess the risk of buffer stop collisions, according to rail accident investigators, following an incident where a train collided with buffer stops at Kirkby station on March 13 2021.

In two other recommendations, the Rail Accident Investigation Branch (RAIB) calls on the Rail Safety and Standards Board (RSSB) to research devices to monitor the alertness and awareness of drivers, and for Merseyrail to improve the way it manages driver fatigue, although this was not a factor in the accident.

Merseyrail 507006 (coupled to 507021) ran into Kirkby’s platform at 41mph (the speed limit was 15mph), hit the buffer stop at around 29mph, and stopped 28 metres further on. RAIB found that the accident’s immediate cause was the driver’s failure to apply the train’s brakes in time to prevent the collision.

RAIB reported that the driver applied the emergency brakes when 110 metres from the buffer stop, while travelling at 41mph. Three seconds later, and 65 metres from the stops, the train’s TPWS (Train Protection & Warning System) applied the emergency brakes. This had no effect because they were already applied.

This TPWS overspeed sensor (OSS) loop was set at 12.5mph to protect the buffers. The previous OSS loop protected the 15mph speed restriction on the station’s approach. Its trigger setting was 53mph. The train passed this OSS loop at 42mph, which meant that TPWS did not apply the brakes.

RAIB said the TPWS was not designed to avoid buffer stop collisions in these circumstances.

The outer OSS loop is designed to cope with trains failing to slow from the line’s permitted speed of 60mph, while the inner loop is set to handle slow speed misjudgements. It is this that prompted RAIB’s recommendation about risk assessments.

Accident investigators say that the driver sent a message from his phone at 18:51:34hrs (hours:minutes:seconds), which was less than one minute before his train hit the buffers at 18:52:24hrs.

They also say that at some point after leaving Fazakerley station at 18:49:45hrs, the driver’s bag fell from its place on the cab’s tripcock cabinet, and the driver reached over to put it back on the cabinet.

Throughout this, the driver maintained pressure on the driver safety device (DSD), which would apply the emergency brakes should a driver become incapacitated and so release pressure on a foot pedal or the traction control level. Thus RAIB concluded that the driver was distracted.

Using his phone contravened Merseyrail’s policy that they should be switched off when driving. RAIB and the British Transport Police re-created the conditions in which the driver retrieved his bag and found that it could be done, but that the driver would lose almost all visibility of the track ahead while doing it.

The train’s driver, Philip Hollis (59) from Walton in Liverpool, was later convicted of endangering persons conveyed or being in or upon a railway by wilful omission or neglect. He pleaded guilty and was given a 12-month jail term, suspended for two years, must do 180 hours of unpaid community work, and pay £340 costs.