RAIB urges improved viewing systems after ‘trap and drag’
The Rail Accident Investigation Branch (RAIB) says London Underground must improve platform camera views, train door systems, training for train operators and the views of in-cab CCTV systems, after a woman suffered serious injuries when her bag was caught in the doors of a train at Notting Hill Gate station on January 31.
In the incident, the train’s operator (the Central Line train was operating under Automatic Train Operation at the time) failed to notice that the passenger’s bag was caught in a door and started the train. The passenger was dragged for approximately 75 metres along the station platform and 15 metres into the tunnel.
An emergency alarm on the train was activated about ten seconds after the train started moving, and the driver applied the emergency brake at about this time. The woman was treated in hospital for about a month.
The investigation concluded that it was likely that the train operator did not perceive the passenger because of a series of factors associated with his task, which caused him not to consciously process the available information.
The view on the in-cab CCTV monitor also did not adequately assist him to detect that a passenger was trapped in the doors, and he relied on other cues to depart from the station rather than thoroughly checking the monitor.
Although the train’s doors are designed to prevent the train’s traction power when they detect an obstruction, the bag’s material was too thin to be detected on the train involved.
Modelling by RAIB showed that the view of the passenger involved on the train’s CCTV monitor did not adequately assist the train operator to detect that her bag was trapped before departure, but that the incident could have been seen on the train’s monitor about four seconds after departure.
At busy times, Notting Hill Gate Platform 4 is manned with staff assisting with train despatch, as it has a reverse curve which prevents train operators seeing the entire platform-train interface without mirrors or monitors. However, at the time of the accident, there were no staff on the platform.
As well as encouraging London Underground to implement a recommendation to review measures that reduce the risks of passengers becoming trapped in train doors (following a similar incident at Clapham South on March 12 2015), RAIB wants the company to ensure door systems on future rolling stock can better detect small objects.
And following concerns about inattention by train operators on ATO trains, due to the nature of their task, RAIB wants LU to implement task-related strategies such as interspersing more regular periods of manual driving, extra task-focused vigilance activities, or providing alerts if an ATO start is attempted before the system is ready.
The third recommendation is to review the presentation of images on platform monitors, including the number and configuration of images displayed to train operators.
And the fourth is to review its competence management programmes for all train operators, to ensure consistency of training techniques for visual scanning of platform monitors and awareness of the limitations of door interlock systems.
A final recommendation is that LU should review information provided to staff about Platform Emergency Stop Plungers (which were not used in this accident), and implement measures to promote the devices’ effective use.