The full extent of the panic experienced by hundreds of “desperate” Tube passengers when a Northern line train began to fill with smoke has been revealed by an official investigation.
The incident happened at Clapham Common station just before 5.45pm on Sunday, May 5 last year – the weekend of the King’s coronation.
A report by the Rail Accident Investigation Branch published on Wednesday told how passengers “turned to desperate measures” to save themselves from what they thought was a potentially deadly fire.
They could be heard “expressing an immediate fear for their safety and calling to passengers on the platform to break the train’s bodyside windows”.
It said they had to wait for four-and-a-half minutes inside the train before station staff began to help.
The train driver did not immediately communicate with passengers on the train intercom – while staff at the Northern line control centre in Highgate could not see what was happening on the platform because the CCTV was broken.
The RAIB report presents the incident in a different light to Transport for London’s internal report, published last December, which praised the station staff for their quick actions.
The TfL report said station went into “evacuation mode” within 45 seconds of the passenger alarm being triggered, when the three staff – a manager with an assistant at the ticket barrier and another on the platform - rapidly realised there was the need to get all passengers out of the station and prevent new ones from entering.
The TfL report said “all detraining was smooth – passengers weren’t rushing”.
But the 51-page RAIB report said passenger fears mounted due to a combination of events – the smell of burning and smoke, the train doors remaining closed, the lack of onboard information and the perceived inaction by station staff.
The train had come to a halt with two of its six carriages inside the tunnel. A passenger, seeing smoke and smelling burning, had pulled an emergency alarm, bringing the train to a standstill. The train’s doors remained closed.
Andrew Hall, RAIB chief inspector of rail accidents, said: “Out-of-course events can rapidly escalate into emergencies if not responded to promptly and effectively.
“During this incident staff didn’t fully appreciate the emerging safety risk when passengers’ behaviour began to escalate as they became increasingly anxious.
“When passengers did not receive suitable information about the nature of the incident and the actions they should take, nor see action they would have expected to be taken, they turned to desperate measures to self-evacuate.”
In addition, the station tannoy began sounding, advising passengers to evacuate. The RAIB report said: “The combination of events led to the behaviour of some passengers to quickly escalate, causing around 100 passengers to self-evacuate the train.”
It said the lack of CCTV images in the Northern line control centre “meant that line control staff had no appreciation of the escalation in passenger behaviour on the platform… until they were informed by the train operator that passengers were climbing out of the train”.
The RAIB made three recommendations to TfL to improve staff training. It said that lessons that should have been learned from a similar incident at Holland Park station in 2013, when 13 passengers climbed out of a Central line train, “may well have begun to fade”.
A “few” passengers suffered minor injuries escaping from the Northern line train. But the incident “had the potential to have more serious consequences”, not least because Clapham Common station has a narrow island platform which increases the risk of passengers falling onto the track.
RAIB’s investigation found that passengers “perceived a significant risk from fire”.
It said that Tube staff were not provided with the training to identify and manage incidents where “passenger behaviour can rapidly escalate”.
The report said that passengers on the train were “clearly distressed”.
When a Tube train’s doors are fully closed, passengers have no means of opening them beyond the ability to pull them open up to around 115 mm against a spring to release trapped objects.
However, station staff can manually open individual sets of doors by using a valve on the outside of the train called the outside door opening device, also known as a “butterfly cock”.
About 30 minutes before the incident, a track fire had been reported near Morden, at the southern end of the Northern line.
The disruption caused by the track fire near Morden resulted in larger gaps in train frequencies, which caused an increase in the number of passengers on the platform at Clapham Common.
In-station CCTV showed smoke emanating from underneath the train’s fourth carriage when it stopped at Clapham Common. Some passengers can be seen reacting to the smoke.
Shortly after the train came to a standstill, the train driver attempted to contact the line controller and used the talkback facility to ask the passengers in car 4 what had happened.
The driver’s to the line controller was not answered as the controller was dealing with another incident. The driver said they could not understand what passengers were trying to say about what had happened.
About the same time, a passenger reported smoke on the platform to the station staff. Two staff went to investigate while a third prevented incoming passengers from entering.
One of the staff reported “heavy smoke” and asked for the station to be evacuated but did not receive a response. A second call was also unsuccessful. In a third call, the staff member on the platform reported that passengers were “panicking”, but again there was no response.
Eventually the train driver contacted the line manager, who was then able to contact the staff member on the platform to authorise the train doors to be opened.
About 15 minutes after the incident began, and as the London Fire Brigade arrived, the last passenger left the station.
The RAIB report concluded: “Once the departing train was stopped by a passenger emergency alarm, passengers perceived a significant risk from fire and became increasingly alarmed when no passenger information announcements were made, and because they could not see any effective action from London Underground staff.
“The proximity of the rising plume of smoke to the open body-side doors makes it probable that the smoke had entered the passenger compartment of car 4 during this time.”
The RAIB said recordings showed passengers told the driver: “There’s a smell of smoke burning in here and it’s extreme” and “There is smoke here”.
A subsequent inspection of the train confirmed that a “strong burning smell” was present within the fourth carriage. Burnt residue and a red clay-like substance was found on the brake resistor grid on the underside of the train. TfL said the substance was grinding paste which is used for rail grinding activities on Tube infrastructure.
The RAIB report said the Tube driver “mistakenly concluded” that passengers were reporting a “brake dust” type incident.
“As a result of this, the train operator believed this was a relatively routine and minor operational incident, which did not require escalation or a ‘mayday’ emergency call to service control.”
TfL has been approached for comment.
