Croydon tram crash: Driver may have been in microsleep

The driver of the Croydon tram crash in 2016 may have been in a "microsleep" when it happened, a chief inspector told an inquest into the deaths.

Seven people were killed and a further 51 were injured when the derailment happened on November 9, 2016.

Dane Chinnery, 19, Philip Seary, 57, Dorota Rynkiewicz, 35, Robert Huxley, 63, and Philip Logan, 52, all from New Addington, died after the tragic accident.

Mark Smith, 35, and Donald Collett, 62, both from Croydon, were also killed.

A senior investigator told the inquest that it was “absolutely clear within hours” that the crash was caused by excessive speed.

The tram toppled over and spun off the tracks after hitting a curve at 73kph (45mph) just after 6am that morning, despite a 20kph (12mph) speed restriction being in place.

All those killed had been either fully or partially thrown out of the tram through the windows or doors when the glass shattered, the inquest heard.

Simon French, chief inspector of the Rail Accident Investigation Branch (RAIB), told the inquest his inspectors had been on the scene by 10am on the morning of the accident.

Mr French said: “The consequence of the tram hitting the curve at 73kph was more than the capability of the tram to stay upright. The tram overturned and slid along its side.”

He said the RAIB had painstakingly matched marks on the tram to marks and damage on the surrounding infrastructure in order to model a reconstruction of what took place.

“At that sort of speed the tram is not going to be able to stay upright on this sort of curve.”

Mr French added: “It was absolutely clear to us within hours what had happened – this was a tram running at too high a speed to negotiate the curve, so we published that very early on with confidence that it was right.”

Mr French said survivors had compared the experience to being in a washing machine, adding: “It was fast and it was violent and it took place in a matter of seconds.”

Jurors were told that trams are essentially mini trains operating in urban environments.

But they have much greater accelerating and braking power than a mainline train, due to their high power-to-weight ratio.

The jury heard that the sharp curve where the tram derailed is immediately preceded by the longest stretch of “low workload” track on the route.

Mr French said the driver, Alfred Dorris, may have slipped into a period of “microsleep” on the stretch were he was not required to do much to control his tram.

“It’s possible there was a microsleep – it’s essentially a very short period of loss of consciousness, a short sleep which all of us can experience from time to time,” he said.

“A trigger of a period of microsleep can be a period of low work – we can switch off when we have low workload.”

Mr French said it is possible Mr Dorris was suffering from accumulative sleep depravation or from disrupted sleep the night before.

He told the inquest: “There’s some evidence that the driver may have thought he was going in the opposite direction of travel, and that can be combined with a loss of awareness – these things can all combine.”

Mr French said extra signage on the stretch preceding the bend could have mitigated the risk, and that the RAIB had alerted operator Tram Operations Ltd (TOL) of the lack of distinctive features.

“The control measures almost entirely relied on the driver’s route knowledge, and a belief that a level of training would protect against this particular risk,” he said.

Mr French also said there were apparent “culture issues” at TOL that meant drivers were unwilling to admit to speeding or other errors.

“If you reported speeding there was an automatic move to a disciplinary procedure,” he added.

There was a previous incident just 10 days before the crash when a driver hit the same bend at 45kmh (27mph) and very nearly overturned, but the incident was insufficiently investigated, the jury heard.

Mr French said one of the primary differences between the railway and the tramway systems in England were that trams are not controlled by fixed signals.

Instead they operate a line-of-sight system, leaving it up to the driver when to brake and when to accelerate.

Trams usually have a top speed of 80kph (50mph), Mr French said.

The 14-week inquest was initially due to begin in October 2020, but was postponed due to the coronavirus pandemic.

It is expected to conclude around August 20.