The driver involved in the Croydon tram crash possibly drifted into a ‘microsleep’ – a nap usually lasting less than a minute – before speeding round a sharp bend, an investigation has found.
Alfred Dorris, 43, from Beckenham, probably dropped off while driving the tram when it came off the tracks in south London on November 9 last year, killing seven and injuring 51.
The Rail Accident Investigation Branch (RAIB) believe it is ‘probable’ he ‘temporarily lost awareness’ on a straight section of track and may have fallen into a microsleep for up to 49 seconds.
Such sleeps can last ‘anywhere from a fraction of a second to a few minutes’ and often involve closing of eyes or head nodding, investigators said.
The driver involved in the Croydon tram crash possibly drifted into a ‘microsleep’ – a nap usually lasting less than a minute – before speeding round a sharp bend, an investigation has found
Alfred Dorris, 43, from Beckenham, woke and was so disorientated he thought he was going in the opposite direction and didn’t believe he was approaching a bend
The tram crash was one of the worst public transport tragedies for a generation
When he roused from his disorientation, he initially believed the tram was travelling in the opposite direction, not realising the bend was approaching.
According to the report, ‘he stated that he did not realise he was approaching Sandilands until the tram turned into the curve’.
Some passengers described the crash that followed as ‘like being in a washing machine’, the RAIB said.
People fell through the openings where windows had smashed and doors were torn off.
They were ‘crushed under the tram’ as it sliding for three seconds and 27 metres before coming to a rest.
It was the worst accident involving a British tram in more than 90 years, investigators said.
They made 15 safety recommendations including operator Tram Operations Ltd, owned by FirstGroup, reviewing its management of driver fatigue, the use of tougher windows and better signage at high risk locations.
Since the accident infra red eye monitors have been installed in each cab on the Croydon tram network as part of a series of safety enhancements.
Tram drivers who responded to a questionnaire issued by investigators revealed that nine of them had previously used an emergency brake to comply with the 12mph limit at Sandilands junction.
Croydon tram crash survivor Taiye Agibola had his face slashed open by glass from the windows that shattered into small pieces (pictured)
Investigators found the risk posed by late braking at the location were not fully grasped by tram managers due to some drivers feeling a ‘reluctance’ to report their own mistakes.
This was the case for the driver who did not report a ‘serious overspeeding incident’ at the same bend just nine days before the fatal crash, in which a tram entered the bend so quickly it almost overturned.
Forensic analysis by the RAIB found that the tram involved in the derailment reached the maximum permitted speed of 50mph as it entered the first of three tunnels which stretch for 500 metres.
It should have slowed down significantly as it emerged from the tunnels on the approach to the sharp left-hand curve at Sandilands junction.
Mr Dorris did apply the brakes but the tram was still travelling at 45mph when it passed a speed limit sign, entered the corner and turned over onto its right-hand side.
He was arrested at the scene and questioned on suspicion of manslaughter and is on bail after last being interviewed by police in October.
The RAIB report is separate to the criminal investigation.
London’s Transport Commissioner Mike Brown said a wide range of additional safety measures have been introduced on the tram network since the crash ‘to make sure such a tragedy can never happen again’.
FirstGroup chief executive said the firm has made a number a safety improvements in the past year including enhanced speed monitoring and restrictions, better signage and renewed guidance on fatigue management.
He went on: ‘We have learned from the RAIB’s analysis and our own internal reviews and we will continue working hard, alongside TfL (Transport for London) to follow the RAIB’s advice and to make further changes where necessary.’