Runaway train on Northern Line: report issued

Oh Dear. That could have ended badly.

ADDED Intervention:

The other thread has now also been removed. Since an RAIB investigation is now definite in view of the proceedings, there is far too much rumour and supposition and guesses in that thread as to what really went on. Sorry folks, the only sources are now the BBC report above and your favourite factual journal the _subStandard .

Some of the details of the internal LU report have now been released to the press. Below is the report by Philip Haigh in Rail #661:

LONDON Underground is implementing 12 recommendations following an incident on the Northern Line on August 13 2010, when a grinding train ran away after a towing bar connecting it to an empty passenger train failed (RAW. 651).
LU is now reviewing procedures and instructions for dealing with rescuing unbraked trains, for approving coupling bars, and for managing incidents involving engineers' vehicles.
The recommendations corne in LU's internal report, and are separate from those that might be contained in the Rail Accident Investigation Branch's report, which is not expected until around a year after the accident.
LU concludes that the accident happened because staff were unfamiliar with the techniques for using passenger trains to rescue engineering trains, and because of flaws in the emergency coupler design and in the grinder's emergency plan.
It found that when the rail grinder entered service in 2002, its rescue plan specified that a battery locomotive should be used, but its emergency coupler was designed for use by a Schema diesel locomotive or passenger train. In the August 13 incident, an empty Northern Line train was used.
The Northern Line train driver used the procedures applicable to rescuing a passenger train, where a 10mph speed limit applies. Emergency brakes apply when this speed is exceeded. However, the grinder's emergency plan says that rescue should not exceed 5mph. During rescue, the grinder's brakes must be isolated because the train driver has no control over them.
During the rescue the emergency brake applied as speed passed 10mph, leading to the coupling between train and grinder failing.
In another departure from usual LU passenger train practice, the grinder was being hauled, not propelled (an earlier incident at West Hampstead on July 17 2010 led to a ban on propelling because it was feared the emergency coupler would dip and hit the fourth rail). When the coupler failed as the train headed north and uphill along the Northern Line near East Finchley, the unbraked grinder started rolling southwards out of control.
The grinder eventually stopped at Warren Street. But as it ran away, LU service controllers had to divert passenger trains from its path, clear station platforms and instruct some southbound trains to keep going without stopping at stations, to prevent a collision. The grinder's crew jumped clear at Highgate.

Acknowledgements to "Rail" magazine

The report is worth reading (if you allow enough time) for all interested in LU operations. It shows how lucky LU were not to have mass casualties, and how engineering can follow the rules and still produce an inadequate design, which then is "tested" and approved, but not in conditions likely to be met in service.

Thread now unlocked to allow further informed comment and observations.

Instead of heads rolling, they were rewarded!

There is no doubt that some quick thinking in the control room saved the day but if those heads are the same ones that decided to use a passenger train to tow the rail grinder they deserve reprimands rather than rewards because that would be a blatant case of reacting to correct a fatal error.

Legally and morally ignorance is no excuse under the law and certainly never has been on the railways. Using a passenger train as the towing vehicle was a misuse of the procedure unless I have misread the report. Such misuse can be construed as incompetence, using passenger trains to tow engineering vehicles is exceptional and thus should attract greater scrutiny than appears to have been displayed before implementing the procedure.
One can easily see that the overriding precedent in the decisions from the control room was to run a passenger service ASAP rather than to use a failsafe procedure to remove the stalled vehicle which would have delayed passenger service considerably.
The behaviour of passenger stock travelling at reduced speed is a 'known' and those coupling the passenger stock to the rail grinder would have been aware of it, it should thus have raised a question about the safe working of an adaptor coupling pulling an unbraked load especially in the light of the known weakness of such an adaptor coupling when pushed!

As is usually the case a single failure of a component, procedure or human seldom leads to disaster, most disasters result from a combination of two or more failures. In this case a disaster was narrowly averted, more by luck than judgement because it was the result of multiple failures, a succession of human failures from the design, testing and licensing for use of the coupling, an inherent failure of the towing procedure to take into account all possible scenarios, failure of control room staff to be familiar with the details of the procedure or worse to waive the most important detail, failure of those on site to see the inherent potential danger or to note the deviation from procedure, i.e. using a passenger train, and to query it and finally, the straw that broke the camel's back, the coupling which was not designed to be used as it was that day.

The towing adaptor coupling was always going to be the weak link and the towing procedure made no provision for its failure.

Human failing from the very top to the very bottom, I certainly can't blame the coupling, no vehicle should ever run unbraked unless it has working brake stock coupled on either side.

Safety first and always, everything else including passenger service must be secondary!

the report says (para 71) that in the West Hampstead recovery last July "an empty train was secured as a barrier between the recovery operation and lines open to public traffic". They could have done that by tipping out train 107 at Archway and leaving it there as such a barrier. It would have resulted in a heavier collision when the greakaway hit it, but it would at least have been empty.

But it's easy to be wise after the event - towing uphill you don't expect a towbar to go into compression - unless you get an emergency stop.

I did not say that I had not read the report but that I had not read it in detail. In fact I read what appeared to be the main parts and the conclusions. A brief general skim appeared to indicate that some procedure was stated in writing i.e. that the coupling was not designed to be used for towing with passenger stock.

As to the control room staff I did say 'IF'. When I have read the report in full and thoroughly digested it I may have further comment but for now my opinion stands.

Well, I have now read the report in full and find it to be a damning catalogue of incompetence.

The report details all the failings in the design, procurement and testing of the adaptor coupler which failed and other approval and procedural matters at senior management levels but the real failure in this incident was not that of the adaptor coupler but the behaviour of all the parties involved, none of whom were trained in recovering the rail grinder and none of whom even considered mitigating the glaringly obvious potential disaster, all trusting in the competence, knowledge and experience of one another.

There is nothing to indicate that the control room staff who averted disaster were not the ones who enabled it!

The control room had no detailed procedure for dealing with the stalled RGU, this was not their fault as it was not policy for it to be held there. However, it was surely service control responsibility to query the procedure to be undertaken and the competence of those undertaking it and otherwise to consult senior authority regarding a safe recovery procedure. Instead assumptions were made and staff on site were working outside the scope of their competences, including the Northern Line Operations Manager. This is where I see a complete lack of discipline, competent staff know the limits of their competencies and must refer to a higher authority to exceed them.

"42 The RGU had successfully completed the rail grinding work planned for the night
of 12/13 August 2010 when, at about 03:30 hrs its engine failed with the RGU
standing in the southbound tunnel about 500 metres north of Archway station (the
breakdown site). The RGU crew found that they were unable to repair the defect
without causing excessive delays to passenger services which normally start in
this area at about 05:30 hrs. Control room staff therefore sent an empty passenger
train from East Finchley station to recover the RGU. This train was intended to pull
the RGU back to East Finchley station, and then into Highgate depot.
43 The assisting train reached the RGU at 05:44 hrs. Staff from the RGU and
the assisting train coupled the trains together using the emergency coupler in
accordance with instructions carried on the RGU (paragraph 80). The RGU crew
then used hand tools to fix the RGU’s brakes in the off (released) position. This
meant that the RGU was now an unbraked vehicle at the rear of the assisting train.
44 Control room staff then gave authority for the assisting train to start pulling the
RGU towards East Finchley (ie contrary to the normal direction of train movements
in the southbound tunnel). This movement commenced at 06:34 hrs."

"72 The only written instructions relating to recovery of the RGU were contained in the
emergency towing procedure carried in the RGU cab. This procedure recognised
that the RGU was an unbraked vehicle at the end of a train but did not include
any mitigation against a runaway if the emergency coupler broke (paragraph 79).
73 The DMT became responsible for leading site activities when traction power was
switched on around the RGU to allow the passenger train to reach the RGU. The
DMT had taken up his post 11 months before the incident after completing a two
year graduate training scheme. He had only received training on the LUL rules
for passenger trains; these did not cover movement of unbraked stock because
passenger train operating staff are not permitted to move unbraked stock.
74 The DMT’s main role at the breakdown site was to ensure effective
communication between the various people involved. He appreciated that the
RGU was unbraked, but understood from the Northern Line Operations Manager
that the RGU could not be moved without releasing its brakes.
75 Witness evidence shows that the Northern Line Operations Manager had checked
that the coupling arrangements were in accordance with the emergency towing
procedure before telling the DMT that the train was ready to move. There is
conflicting evidence about whether the ERU staff on site also told the DMT
that the train was ready to move. Recordings of radio messages show that, at
06:28 hrs, the DMT informed control room staff that the train was ready and, at
06:29 hrs, control room staff gave the train operator formal authority to commence
the movement.
76 When LUL’s Northern Line control room staff authorised the tow to commence,
they did not apply any special procedures relating to runaway risk because:
l there was no special procedure in place to cover this situation (paragraph 79);
and
l staff at the breakdown site had not asked control room staff to provide any
special precautions and, based on previous experience working with the ERU
and the Northern Line Operations Manager, the control room staff felt confident
that site staff would manage the recovery safely. Witness evidence is that the
control room staff were unaware that the RGU was unbraked but, even if they
had known this, their confidence in the site staff meant that they would still have
authorised the tow."



"206 None of the control room staff, or train operators, dealing with the consequences
of the runaway RGU had any experience, training or guidance on how to handle
this type of situation. Their performance, and particularly that of the service
manager, deserves commendation."



"224 LUL reports that managers have discussed the incident with relevant control
room staff and that issues arising from these discussions, together with issues
identified by the formal LUL/Tube Lines internal investigation of the incident, will
be included in a planned training day for controllers. These issues include the
resumption of normal southbound train services between Archway and Camden
Town at about 07:12 hrs, before the line had been examined. This was an error
– the line should have been examined to check for possible damage by the
runaway RGU."


Para 206 indicates that control room staff should be commended but all their actions leading up to the authorisation of the tow and their failure subsequent to the runaway suggest the opposite!

Clearly this was a case of the blind leading the blind and nobody wanting to rock the boat!

Key point!!! Nobody realised that if hauling, a situation could arise with the same (compressive) forces as propelling. And nobody twigged that if the 10mph limit was exceeded by the tube stock in restricted manual, an emergency brake application would happen - and the compressive forces by the RGU on the towbar would be massive (as bad as, if not worse than, propelling)!!!

Railtechnician has it right - the blind leading the blind and all asses being covered!!!!!

If we're gonna start pulling out specific paragraphs, let's not forget the first two:

1 The sole purpose of a Rail Accident Investigation Branch (RAIB) investigation is to prevent future accidents and incidents and improve railway safety.

2 The RAIB does not establish blame, liability or carry out prosecutions.

It's been suggested that trust in the competence of others should have no place on the railway - that is a load of cobblers.

As a driver, I am trained to deal with defects on D stocks. Control room staff are not, and nor are duty managers. They have to trust my competence as dealing with rolling stock defects falls outside their job boundary. It's much the same as when there's a signalling defect, or traction current supply issues or whatever else; the control room staff have to rely on other people on the ground that are trained and have the relevant competence.

Control room staff can make suggestions to help resolve an issue but is down to judgement of those on the ground as to whether they follow any such suggestion. Equally, staff on the ground may request certain actions from service control - an assisting train perhaps?!!

Remember also that this was an engineering hours issue (generally outside the remit of service control) that over ran into traffic hours and thus into the domain of service control. I have every confidence that the staff involved were following what they felt was the best course of action to resolve the issue as quickly as possible for all parties. Of course they had the passenger service in mind; after all that's the whole point of the railway isn't it?!!

One last point....if a D stock is required to be pushed out by an A or C stock, we have to release and cut out all the brakes. If the D stock should then break away from it's assisting train, it will be an unbraked vehicle - the same could happen again any time and it could just be bad luck!!

Sitting here humming the Michael Holliday song about the runaway train, WTF, we have a graduate who does not have the common sense not to allow unbraked vehicles to run?? The mind boggles. I think we all appreciate that at times the railways DO have to run something unbraked, indeed for over 100 years goods trains ran with only a brake on the loco and the brake van without too many problems.

Why do rolling stock manufacturers not provide a hand operated parking brake for such contingencies?

What Colin says is also spot on. When I was a driver, I relied very heavily on the 100% competence of other to assure the safe passage of my train.

The problem with incompatible couplings hes been with the railways since their inception and continues to this day. I think the nearest we got to standardisation was in the 1960's, with "most" things on LT either Ward or Wedgelock, and on BR the standard hook and links or Buckeye couplers. But then we had different braking systems...

The coupling arrangement is the Wedgelock coupler - naturally it should never fail, but of course only a fool would believe that. In actual fact there is a fundamental flaw in the Wedgelock design; it needs air to hold the wedges in position....otherwise you are only "mechanically coupled".

Now I have to admit to a schoolboy error in that I had omitted any thought to the spring applied parking brake That said, it's actual purpose is only to prevent a unit from rolling from standstill - it isn't a brake that can be considered capable of bringing a moving a unit to a stand. In fairness it probably would, eventually, but there is no knowing how far a unit could travel in that circumstance.

The reason I omitted it was that when we go down the road of pushing out a D stock, we cut out all the brakes on the dud unit(s) - and push through the spring applied brake - so there is now no emergency brake available to the train operator in the leading cab. The only actual proper brake is on the assisting unit. The point I should have made is that it is quite possible to have a push out scenario whereby you might be expected to place your own safety in the hands of others, and that you can be on a failed unit that's receiving assistance with no emergency brake available.

What is very clear is that the situation was exceptional but cannot be seen to have been dealt with as such.
The RGU crew knew they needed a tow, the DMT was just a communicator, the ERU were there to assist as was the driver of the assisting train, we don't know the role of the Northern Line Operations Manager and even if he was the senior man on site we don't know if he took charge, though it appears so.

The control room staff sent an assisting train but we don't know who requested it and once it was at site and coupled up it is not clear who had decided that it was safe to move, certainly not the ERU, it seems, who might normally have been expected to be taking charge but apparently were only bystanders.

Apparently nobody on site was trained or licensed to undertake the manouvre so there was nobody qualified to take charge and to ensure that what was about to be done was safe.

The control room staff on a 'need to know basis' were also not required to know or understand the procedure for towing of the RGU so left it to the 'competent' staff on site. One might have thought that as it was 'their railway' i.e. they might have asked some questions regarding the exceptional manouvre.

Back in the day the golden rule in exceptional circumstances was that "all parties must come to a complete agreement about what is to be done" and the reported evidence does not indicate that this was the case. It seems that the acknowledged experts, the ERU, were at best not listened to and at worst ignored, had they been in charge they would no doubt have sought knowledge from a higher authority as they had not dealt with towing an RGU before. Thus the whole operation can be seen as managed and carried out by LUL staff, none of whom were qualified to do so!

Colin stated "It's been suggested that trust in the competence of others should have no place on the railway - that is a load of cobblers. "

Don't suggest something that I did not say! In bygone days competence was gained through knowledge and experience and by the acknowledgement of one's peers and supervisors but nowadays 'competence' is measured by 'licenses held' regardless of knowledge, experience or in some cases competence as long as one passes the assessments.
Clearly nobody on site was licensed 'to tow' or 'to oversee the towing' of the RGU and neither was anyone in the control room, but nobody queried or established who was in charge and by what authority and that is the crux of the potential disaster.

The incident highlights a big hole in the management of risk which should have been identified at the highest echelons of LUL and Tube Lines management but which was overlooked by them on numerous occasions.
It also identifies a lack of appropriate licensing and lack of procedure indicating a clear chain of command and the necessary human resources required to carry it out.

There is no doubt that this was a very serious incident, Colin and Tom state that it was an Engineering Hours issue and that, that somehow exonerates the control room staff, the DMT and the Operations Manager. I agree that the DMT was just a communicator but the Operations Manager and the Control Room staff should have deferred to those qualified to deal with an Engineering Hours incident as what was being done was clearly beyond the limits of their own authority. They didn't, we can speculate why not but it really isn't important as that was the fatal error which everyone is trying to cover up with red herrings.