The Northern Line Runaway: Links and Facts

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Friday saw that rarest of events on the Underground – a truly “runaway” train on the Northern Line. Now that a short period has elapsed, it seems a good time to summarise events based on what sources have reported. Obviously, a real assessment of events will have to wait until the RAIB report on the matter – a report that will no doubt be both thorough and enlightening. As things stand, however, (and as my colleague Mwmbwls similarly commented on the RAIB’s report into the Piccadilly/District incident released earlier in the year) it appears that a combination of minor events led up to the runaway, and that quick thinking and good training on the part of Underground staff helped ensure a serious incident was avoided.

The official TfL press release on the incident is here, and the BBC have an article up here.

From these and other sources, it appears that the incident originated early on Friday morning when an Engineering train (more specifically a rail grinder unit) suffered electrical issues and became defective near Archway. A decision was made to use a regular unit of 95 stock to move the defective train so that normal service could be restored and a unit was dispatched from the depot at Highgate for this purpose.

As the failure had taken place on the southbound line, a Wrong Directional Movement was thus required. The defective train was prepared in line with guidelines and then attached to the towing unit with chains (as it lacked couplings) and its brakes released.

Unfortunately, the emergency coupling failed as the movement was taking place and the engineering unit became a “runaway” just outside of East Finchley at about 6:44am. The line from East Finchley down is effectively an incline, and thus the defective unit began to move in that direction (i.e. now running southbound in the “correct” direction for that length of track) whether the unit was equipped with tripcocks is currently unclear, but it is worth remembering that even if it had these would have been isolated as this had been a wrong directional manoeuvre.

With the defective unit now moving southbound, the line controllers decided to run the southbound passenger unit ahead of it at Archway non-stop to Camden and then on to the Bank branch. The platform at Camden was also evacuated.

The defective unit was then allowed to run southbound all the way to Warren Street on the Charing Cross branch, where the track slope changes and the train would come to a stop. This it did at approximately 6:57am. Any staff still on it when the incident began evacuated as it passed through Highgate, and the points at Mornington Crescent were deliberately reversed in order to help slow it down en route to Warren Street (naturally becoming damaged in the process – a contributing factor to the subsequent delays).

Obviously the above represents the barest of facts, and the RAIB report will go into more detail. When it does, we will cover it here.

On a final note, whilst it is important to establish what went wrong and what could have been avoided, it is also worth remembering that during the incident Underground staff performed impecably, and it is a testament to their ability that a more serious incident was avoided. In that vein, we will quote from the Fact Compiler whose thoughts largely reflect our own here at LR Towers:

Without wishing to prejudge this, or indeed add to the media frenzy, the Eye would like to make mention of various people to whom the Underground and Londoners owe a debt of thanks.

So firstly a deep doff of the bowler to the Northern line controllers and signallers who responded so well to an unprecedented situation, cleared the line and by so doing prevented an incident of far greater magnitude taking place.

Eye offers another doff of the bowler to the Northern line motormen and women (Train Operators) who, when faced with a whole set of new instructions over the radio, put their faith in what they were being told by Control and got on and did it.

The Northern line [was] led by General Manager Jeff Ellis.

[Note: Mr Ellis has in fact recently moved on and Pat Hansbury is now in charge over at the Northern Line, but the comment is still valid – JB]

Jeff is a heavyweight railway operator, who cut his teeth as railway incident officer for the Moorgate accident. Although one of a dying breed in an increasingly politicised TfL, Jeff will have inclulcated in his team a professional approach to railway operations.

These tried and tested skills served Londoners well on Friday.

UPDATE: The RAIB have released a statement

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.

Thanks to Anonymous for the spot

Written by John Bull
John Bull is the Editor of London Reconnections. A transport journalist and historian, his writing often focuses on the political or strategic challenges facing London's transport network and beyond.