Fire in Stockholm Metro

This has to be the worst situation staff and passengers could come across. It's pleasing to read that not one person was fatally injured.

I've just finished speaking to Igelkotten, the latest news is that Engineer's loco 9201 was sent to Rinkeby this afternoon to move the stock back to Hammarby Workshops for further investigation.

Services on the Red Line this afternoon peak will be a train every ten minutes, suggesting that all the peak hour extra trains (and Line 13 shuttles) have been cancelled. (These are all booked to be operated by Cx stock, the type involved in this morning's fire.)

I'm sure he will be along later to post a further update.

Well, it didn't take much investigation to have that "sabotage" theory fall to pieces, despite certain press officers among the police force and Connex seemingly being in love with the idea.

As it turns out, it seems to be something of a nostalgia extravaganza: A traction motor fire, much on the lines of the ones we had on the C4 stock back in the mid nineties.

Based upon what I have heard from colleagues, certain people who were on site and a few other sources, this is my take on what might have happened. I must point out that the formal investigation has only just begun, so I could be talking utter ball hooks here.

Anyhow; car no. 1301, a C14 stock car, thyristor controlled and delivered in 1986, running in a married pair with car 1300, was the seventh car in the eight-car train 324 on line 10. On it's way north from the central station to Hjulsta, something went wrong with the traction system. The driver tried tripping and resetting the line breakers and contactors a few times -accounting for the "bangs underneath the car" some passengers reported having heard.

Somewhere around Duvbo-Rissne, something happened with the traction motors in one of the bogies -possibly a heavy flashover or a short circuit. This, in turn, started a fire, and probably sent some extreme surges through the high voltage circuits, in turn causing more damage. A fire started, probably in the motor and then spreading to other underside equipment. A mixture of oil, iron filings and dust -the usual gunk caked on a car's underside- started to smoulder, giving off tremendous amounts of smoke.

As the train arrived at Rissne, other staff had already began alerting line control that they could smell smoke, and seen a bit of smoke come wafting throuhg a tunnel. Then, the driver of train 324 broke in with an emergency message over the radio, stating that he had a heavy smoke condition and a fully developed fire in his train.

From thereon, things proceeded much as I have described above. One of the supervisors responding to the scene described the car as "jumping in place,with a terrible screeching noise" and also observed extremely heavy arcing from the underbody equipment.

On the car, at least one motor bogie, the resistance grids, the line filters and inductors and a few other things are reportedly mostly molten slag. Likewise, in the car itself, the passenger saloon has seen extensive damage, and the solebars apparently looked "kinda weird".

It is worth noting that the rolling stock maintenance company, Tågia, has recently faced severe criticism for shortcomings in the maintenace of the rolling stock -including traction motor maintenance.

Another intersting issue is how the fire could catch on so quickly, and how it could become so violent. This gives rise to all sorts of question marks over the materials used in the refurbishemnts of these cars, as well as the maintenance.

Our local Health & Safety reps stopped the use of all non-C20 stock in the metro today, leading to uttter chaos on the red line during the afternoon peak. This was due to uncertainity over the techincal status of the cars and whether they were safe to run in service or not. The Health & Safety Inspectorate has withdrawn this stop late tonight, but it is not clear whether Connex will accept using old stock tomorrow, or even if Tågia or Stockholm Transport will allow the old stock to be used. It might be that C14 stock is sidelined for a few days, but C6 is permitted to run in service tomorrow.

As I said, to me, and quite a few other old-timers, this sounds like a repeat of the C4 fire epidemic from the mid ninties -overworked and under maintained cars eventually do break down, sometimes in a spectacular fashion.

I would no be all that surprised if I learned that certain Tågia managers were covered in cold sweat right now.

As of 01:00 this morning, the clearign of the station was still in progress. While the plan is for the station to be back in service tomorrow, there are still a lot of things to do and investigate befor that is possible. Not to mention the clean-up. And getting rid of the smell of burnt rubber and cabling!

The damaged cars had, when I went home, still not been transferred to Hammarby for investigation yet. It might be that they will conduct the investigation in Rissne depot, or the cars will be moved at a later date.

Oh, and since the accident is deemed as being of "extraordinary interest, and having possibly very sever consequences", it is going to be investigated by the national Accident Investigations Board, not the Railway Inspectorate. This is about as high up in the accident investigations chain you can go within the country.

Metronet seem intent on running "our" trains into ground too. Anything reported to depot and proved by a road fitter is then not found in the depot and returned to service in the state it was reported. All defects have to be repaired within a set period of time, otherwise Metronet is penalised. However, if no defect is found, they get off scot free and penalties are no more.

There is going to be a time where we will suffer the same fate through metronets unwillingness to play ball. I'm not suggesting that our trains are unsafe, otherwise you wouldn't find me driving one, but we are going to have a train sit down with a rather large defect sooner or later.

I got a phone call from a past trainee the other day with an MA defect. He'd got it into Parsons Green sidings out of service and was just confirming with me that he'd done the correct thing, which of course he had. The Ma was running erratically and the batteries were virtually dead as a result. I'd reported the same unit 3 weeks ago with the first signs of that defect and got a changeover!!

The fitter turned up. Now who this fitter was, god only knows, but according to this fitter, if you get tripped the ma light goes out!! How did this driver get the train limping into the sidings if the train had no train line air because if was tripped!! and since when do you lose your MA indications when you get tripped. These are meant to be professional road fitters who also spend time in the depots maintaining trains.

I told the driver to put this in his trainmans report should he be required to make one. The thing that wound me up about it, is that certain DMT's have no knowledge of trains. This driver could have been up for an aggrivated SPAD on the words of this alleged muppet fitter.

I know, but won't it be more pleasant for you to hear something like 'Hi chief, something has just exploded under the train, and the car is full of smoke, can you take care of that, please?' over the intercom instead of PA buzzer ?

Of course when we eventually get the refurbed D stocks into service ( ;D), they are fitted with a talkback facility, which means we'll be able to find out why the handle has been operated without leaving the cab.

And I think I speak on behalf of my London Underground colleagues that we'd like to know too.

I assume this is the same sort of powder system that's used in racing cars; I know it's supposed to be very effective.

I do know that most modern Metro stock in use in Spain do incorporate a sprinkler system for fire extinguishing, but that is based on water with certain additives, similar to the AFFF foam used by fire services.

Spain, by the way, has some very impressive Metro systems. And they keep building extensions, and getting them done within the timeplan and under budget. Must be something in the water, or something.

Yes, there are handheld fire extinguishers (CO₂ kind) in every car. I've seen them in action twice (driver 'treated' a smouldering saloon lamp). But I meant another thing...

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www.epotos.com/igla/igla_m5kt.htm

Automatic fire detection and extinguishing system "IGLA-M.5K-T"

Purpose.

System is intended to discover fires inside protected compartments of Metro cars, extinguinsh them and monitor extinguinshing efficiency.

System can extinguinsh solid inflammable materials, inflammable liquids and electric equipment unger the voltage up to 5000 V.




Principle of operation.

Heat notifiers and powder extinguishing modules are installed unside inflammable compartments being protected.

Heat notifiers use a battery of serially connected thermocouples as thermosensitive element. If temperature inside a protected compartment raises above 72±3^o and/or increases faster then 5^o/second, a visual and audible warning is triggered inside driver's cab.

Central Indication Unit displayes information about fire - car number and name of the compartment where temperature raises.

If fire has been detected, system discharges current on the affected car to prevent arcing. After that, in 3 seconds extinguishing modules are engaged. All information is represented on Central Indication Unit in real time.

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As entire Moscow (more than 90% undergroung) and St. Petersburg Metros (entirely underground, except depots) are equipped with 'Igla' system, I don't think it can posess a health hazard. At least, powder is not poisonous . And it will snap into action inside a car only if there is a fire there; if traction motor (or another underfloor equipment) would catch fire (more likely event), extinguishing powder may aviod saloon completely.


Side note: I've translated only the most interesting parts of the page I've reffered above; if you need entire page to be translated, drop me a note.

I think the word I'd use is probably'undesirable' rather than hazardous, though I'll happily stand corrected on this.

So far as I can recall I've only ever seen them used in small and confined spaces - hence my reference to racing cars, and I think quite a few other 'engine space' type environments too - I know they're popular amongst the boating community for automatic systems where they (again) discharge into a confined space.

Ours are de-ionised water (or water with additive, depending on who you listen to). Apparently they're safe to use on electrics, though I wouldn't like to put that to the test...

IIRC they are safe to use on train fires, providing traction current is switched off first. ie, they are suitable if there is only low voltage current, but not high voltage current present.