UK RAIB Investigating Runaway of Engineering Train from Highgate to Warren Street of the London Underground
Press release from the UK Rail Accident Investigation Branch:
The RAIB is carrying out an investigation into the runaway of an engineering train which occurred on the Northern Line of London Underground (LUL) on Friday 13th August 2010.
The train consisted of a self-propelled diesel-powered unit designed for re-profiling worn rails. It had been working between Highgate and Archway stations on the southbound line during the night of 12/13 August. At the end of grinding operations that night, the crew of the unit found that they were unable to restart its engine to travel away from the site of work.
An assisting train, consisting of a six-car train of the 1995 stock used for passenger services on the Northern line, was sent to the rescue of the grinding unit. The assisting train was coupled to the grinding unit by means of an emergency coupling device, and the braking system of the grinding unit was de-activated to allow it to be towed. The combined trains then set out to run to East Finchley station. At about 06:44 hrs, after passing through Highgate station, the coupling device failed and the grinding unit began to run back down the gradient towards central London. The crew of the grinding unit, who had no means of re-applying the brake, jumped off the unit as it passed through Highgate station. It then ran unattended for about four miles, passing through a further six stations, and came to rest near Warren Street station about thirteen minutes later. No-one was hurt.
There was some damage to the grinding unit, and points at Mornington Crescent station were damaged when the unit ran through them.
LUL control room staff took action to clear trains away from the path of the runaway unit. The RAIB’s investigation will seek to identify the position of these trains in relation to the runaway. It will also consider the reasons for the failure of the coupling, and the rules and procedures applicable to the rescue of failed engineering trains.
The RAIB’s preliminary examination has identified no evidence that the condition of the track or the signalling system contributed to the incident.
The RAIB’s investigation is independent of any investigations by the safety authority.
The RAIB will publish a report, including any recommendations to improve safety, at the conclusion of its investigation. This report will be available on the RAIB website.
The press release was posted here: