Braking issue on Caledonian Sleeper causes train to "run away" at Edinburgh

Discussion in 'UK Railway Discussion' started by 87015, 1 Aug 2019.

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  1. GB

    GB Established Member

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    The passenger stock is designed to work with locos...locos that require manual manipulation of physical equipment....how are your "microprocessors" going to help? Or are you saying all locos that require a degree of manual handling should be replaced?
     
  2. jfowkes

    jfowkes Member

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    There will always be issues with an interface between technology and humans. Look up flight 401: an airliner crashed because the entire flight crew became focused on a faulty indicator light rather than actually flying the plane.

    The solution was not more technology (like a faulty-indicator-light indicator light), but better training and procedures. Crew Resource Management became a thing.
     
  3. aleggatta

    aleggatta Member

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    The largest proportion of passenger carrying rolling stock for the last 20+ years to be introduced has been multiple units, they have electronic safety systems and electronic brake control. The fact that the first sets of coaching stock to be introduced has in recent times have been struggling with multiple braking issues (MK 5 + 5A) it surprises me that the new coaching stock has been built to (relatively) antiquated standard coaching stock braking systems, and not being equipped with multiple unit style braking systems that would simply require the loco's to be modified in the same way that others have been already (i.e. translation equipment fitted to the likes of classes 57/37 used for multiple unit drags). Why should we not be moving on with more modern standards the likes of brake continuity wires and energise to release braking systems when they have the fail safe systems that would have prevented this incident from occurring. Simply put there is a system that is safer by design, and that really can't be argued with.
     
  4. captainbigun

    captainbigun Member

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    Wow there’s a pile of sweeping statements and generalisations there.

    In what way is the braking system antiquated? It’s KB kit found in many other places.

    How is brake translation simple?

    Brake by wire is entirely safe and not subject to faults?

    Sorry, some folk need to get a grip.
     
  5. O L Leigh

    O L Leigh Established Member

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    MU stock with an EP brake still requires a brake continuity check after coupling, even though the process is somewhat more straight forward than for a two-pipe train. However, the principle still exists that brake continuity must be correctly checked to ensure all is well before setting sail.

    Let’s try and keep a sense of proportion here. This isn’t about “the railway knows best”, but rather about understanding the incident and implementing an appropriate response. There’s no need to be losing our heads and rushing about making unrealistic demands that this or that be done.
     
  6. ComUtoR

    ComUtoR Established Member

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    For our units, this check purely checks that there is brake continuity and nothing more. You only check the brakes have released and are matched between cabs. This only checks 2/8 (4+4) coaches for brake pressure.
     
  7. O L Leigh

    O L Leigh Established Member

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    Quite. But that is still a test of brake continuity.

    My point is that even if you did opt for an EP brake, it’s operation still requires testing. Simply throwing electrical control equipment at the problem does not solve it as it’s operation cannot be assumed must still be checked.
     
  8. HSTEd

    HSTEd Established Member

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    Why do the locomotives require manual manipulation of physical equipment?
    Why were they not fitted with fully automatic couplers like those fitted to other modern passenger stock?

    You've already fitted with them with specialised couplings.
     
  9. Justapunter

    Justapunter Member

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    Correct. And you make it so it can’t set off until it’s been checked. And the driver makes a positive inout to confirm it
     
  10. GB

    GB Established Member

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    Probably because they are still required to haul freight and other passenger stock.
     
  11. O L Leigh

    O L Leigh Established Member

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    Eh...? Why are you agreeing with me? There’s nothing in what I’ve said that supports the notion that this situation requires greater technological complexity to deal with it.

    I’m unsure if you’ve simply misread my post or if you still don’t understand the principles and mechanics of train braking systems.

    I would also like to dispel the myth that an MU style EP brake is somehow more failsafe than a two-pipe brake. Having an EP brake doesn’t give you any greater protection against a brake isolation cock being in the wrong position. The only real difference is that you cannot release the brake if the main res pressure is too low, something that I don’t believe affected the Cally Sleeper.
     
  12. Justapunter

    Justapunter Member

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    The technology is to make sure the manual job has been done. Not to do it. The job clearly hadn’t been done. So add in a failsafe.
     
  13. ComUtoR

    ComUtoR Established Member

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    But you are not adding a 'failsafe" you are adding in another check.

    465 - Physical and mechanical checks to confirm everything is ok.

    376 - Electrical test with confirmation light that you have continuity.

    Some would say that the 376 is superior because it has the computer ensure that there is brake continuity but it is just another form of check. It still requires the human up front to confirm everything.

    A 'failsafe' system is exacy what it states. When there is a failure, it fails in a way that is 'safe'

    Adding more and more checks and balances still doesn't account for the times where the system is deliberately isolated (or indeed accidentally) or when the system fails.

    In this current scenario. I can't see where anything actually 'failed'.

    Now take a 700.

    This beast is computer based. Yet they couldn't go anywhere in their recent incident because 'computer said no'

    However, even with a 700 you could still isolate the braking system or override it. You will still have a situation where human error will override any safety system.
     
    Last edited: 13 Aug 2019
  14. aleggatta

    aleggatta Member

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    I would like to point out one distinct difference with regards to overriding braking systems - In the situation with the Mk 5's, one isolating cock was left in the wrong position, and the brakes on the entire consist failed. On a multiple unit, that is not the case.

    For my example I will use an Electrostar, to manually release the brakes to create an unsafe situation, you have to isolate one cock on each coach that is below the sole bar, it has to be intentional. If you lose main res pressure the brake continuity wire is broken so the train can still stop with the air available in the brake reservoirs. if you get a hole in one of the brake reservoirs, a governor opens the brake continuity wire and stops the train whilst it still can with the air it has available from other reservoirs. All coaches report back on Mitrac a brake cylinder pressure and if one is out compared to the others it flags a fault. If the brake continuity wire is broken from the back of the train to the front the train does not move, Brakes are released by an electrical signal, not applied by one. that is how fail safe works, there is even a governor on the parking brake release to inform the driver of a parking brake application. This situation shows that obviously the brake pipe is not always a fail safe system if it can be operated in an incorrect manner unknowingly. On a multiple unit if any isolation is not in the normal 'passenger service' position, it will flag a fault and the driver will be aware of it. I really struggle to see how it can be justified that there is not a problem with the system on the mark 5's in its current form. Even if they just gave the driver a stop button in the cab to trigger the stop system on the coaches (the one that the guard operated) you would have a safer system than what you have currently.
     
  15. TimboM

    TimboM Established Member

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    As part of the CAF/Mk5 mods to the 92s an intercom/handset was fitted to the cab for communication with the train. That still requires it to be working (works via the less-than-robust 61-way jumpers as far as I know) - back-to-back radios are used as a back-up.
     
  16. 43096

    43096 Established Member

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    There seems to be an awful lot of reinventing the wheel on this thread! The two pipe air-brake system is a fundamentally safe and reliable piece of kit. In this case I rather suspect that, assuming the brake test was carried out before leaving Carstairs, there wouldn't have been an incident if standard air pipes were in use rather than the Dellner couplers. That is because the closure of the isolating cock was presumably accidental - with standard air pipes it is very difficult to accidentally close a cock as they are latched (after the Darlington incidents referred to previously). It will be interesting to see what the RAIB investigation makes of the brake system design of the Mark 5s and the risk of accidental closure of isolating cocks.
     
  17. NSEFAN

    NSEFAN Established Member

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    If this is indeed true, then a combination of better training for staff using the coupler, and better design of the isolation to make it harder to use in error would help. If not already fitted, perhaps some additional warning to the driver when the isolation is in use (warning light / message that requires acknowledgement of some kind)? Isolation for emergencies will always be necessary to have, so the braking system probably doesn't need a complete re-enginerring as some posters are suggesting. Nonetheless, it appears that it aught to be more difficult to use the isolation by accident and without staff noticing until it's too late.
     
  18. Harbon 1

    Harbon 1 Member

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    If you were to have an indicator to show that the isolation cock was closed, it would be on all the time as the loco requires the cock at one end to be closed to create a brake in the first place. What if the indicator fails? Is looking at the brake pipe and seeing the cocks down not good enough to continue? Also, without knowing these locomotives, the dellner fitted examples appear to have multiple fittings on both ends, therefore there will always be isolation cocks closed somewhere on the loco. Isolating for an emergency is completely different and as I read this situation, no emergency isolating cocks were touched.
     
  19. O L Leigh

    O L Leigh Established Member

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    I don’t recall the brake cylinder monitoring via the MITRAC from my time driving Cl379s, but I’ll take your word for it. It’s been a few years and the precise details have already faded.

    However Electrostars are an unrepresentative example, as a lot of MU trains with EP brakes do not have this feature nor any in-cab warning that a safety system has been isolated elsewhere in the train. There are, therefore, conditions where the train brake may not fail safe (those in the know should know what I’m talking about, as I’m not going to elucidate further on this point).

    Obviously there are restrictions in place for moving any train in such degraded circumstances, and this is where Human 1.0 comes into effect. There are procedures on the depot that ensure that everything is done correctly and a train passed fit for service before being released, train prep by drivers and/or depot staff and train handover procedures where crews are relieved en route. All of these things are done for your safety whenever you catch a train.

    To apply your MITRAC idea to the Mk5s, you’d be looking at some sort of decentralised computer network with a microprocessor on each car communicating with all the others. It’s not a trivial matter to set this up and then getting it to work with a loco.

    Could the Mk5s have been built with an EP brake, controlled either through the jumper cables or a connector block? Yes they could. It’s also possible that the locos could have been provided with translator equipment to translate brake pipe pressure into electrical control signals. But they chose not to, presumably because the existing two-pipe brake technology is sufficiently well understood and well-proven that departing from the established system for loco haulage was not considered justifiable.

    Would an EP brake really have conferred much of an advantage? Yes there was an error when forming up this particular train, but there have also been errors when attaching and detaching MUs that have resulted in incidents together with EP brake faults and failures that have affected the braking performance of individual trains (I know because I’ve had one myself). At the risk of yet more repetition, this is where railstaff carrying out the appropriate checks guards against problems becoming incidents.

    And this is what I’ve been saying for a while now. All the signs are pointing towards this being a process failure rather than a technological failure. Like you, I suspect that the unconventional means of coupling the coaches and making the air connections may have caused some confusion for the ground staff which, together with incorrectly brake-testing the train, caused it to leave Carstairs with the brake pipe isolated between the loco and train. There are no fault conditions that could not have been identified and rectified had the train been correctly brake-tested and, as such, the appropriate response would be a tightening-up of the procedures to mitigate against a repeat.
     
  20. Bromley boy

    Bromley boy Established Member

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    It’s most likely one of many inputs that will flag a generic “brake fault”, rather than something that can actively viewed through the MITRAC menus.
     
  21. GB

    GB Established Member

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    How do you know the brake test wasn't carried out correctly? How do you know the cocks were not closed/knocked AFTER the brake test was carried out?
     
  22. O L Leigh

    O L Leigh Established Member

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    I don’t. Do you? It strikes me as highly likely, though.

    What I’m trying to impress is that the existing checks carried out correctly would highlight a brake fault in a two-pipe train and that the clammer for a technological solution is not necessary.

    **EDIT**

    I accept that it’s possible that there’s another explanation for this incident, such as the one you suggest. But if you felt that you’d knocked, snagged or caught some part of the train in the course of your duties, wouldn’t you have at least thrown a glance back just to make sure that everything is as it should be before stepping away? I wouldn’t suggest that it’s necessarily the case that you’d need to brake test the train again, but if there was any doubt then perhaps it’s not the worst idea. Perhaps the shunter wasn’t aware. I suppose that’s possible, but I’d find it a little surprising given that cocks are deliberately stiff (stop sniggering at the back) to prevent them changing position due to gravity or the motion of the train, etc. If you’d snagged one with your jacket sleeve, for example, you’d almost certainly have felt it.
     
    Last edited: 14 Aug 2019
  23. The BIgman1234

    The BIgman1234 Member

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    I was a shunter (passenger) for 7 years and never ever heard of the cocks being closed after the brake test had been completed.
    I’ve seen couplings not put on , ETH jumpers not put in and seen them ripped out as well . Rumours are that the cocks were closed after the brake test but all speculation and we will need to wait for the enquire.
    If you didn’t open the cocks properly the air would escape and you could hear it right up the platform . Plus the driver wouldn’t have hadthe proper air pressure . Guess we will just need to wait and see what really happened.
     
  24. Greybeard33

    Greybeard33 Established Member

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    Quite. There has been a lot of speculation on this thread based on few confirmed facts. In some posts there has been implicit criticism of the actions of the shunter, driver or guard. Some posts have implied that CS operational procedures and/or training were deficient or inadequate. And there has been criticism of the specification and/or design of the braking system and coupling configuration.

    In the interests of all those involved, who may be at risk of disciplinary action, would it not be better to wait until a RAIB report details what really happened?
     
  25. 43096

    43096 Established Member

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    Shouldn’t the brake test be carried out after everything else has been completed, so staff are not still working around couplers, isolating cocks etc.?
     
  26. GB

    GB Established Member

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    The brake test should be the last thing done, yes. But not everything in life always goes to plan. Cocks can be isolated after a brake test if the loco develops a fault and you need to identify if its a problem with the loco or part of the train. They could be isolated if the brake pipes need splitting and reattaching if an air leak is noticed or they weren't initially connected properly, or you require to split the pipes to create more room "in between" in order to reconnect electrical connections.

    I am not saying any of this is what happened, just that it might not necessarily be the case that a brake test wasn't carried out. As someone said above, the report will reveal all.

    It might surprise some people to know that there are times (at least on freight) where no air continuity test is required if a loco has detached and reattached.
     
  27. The BIgman1234

    The BIgman1234 Member

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    Maybe surprise some people that years ago we ran freight trans with no brakes just a brake van at the back .. unfitted class 9b trains .


    Thankfully they were just getting done away with when I became a signaller and I didn’t need to learn areas of restraint:smile:.
     
  28. Alanko

    Alanko Member

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    I can't add anything to this discussion, but I witnessed the aftermath of this incident without realising it. While waiting for Tornado to appear in Waverley I noticed that North Berwick and Galashiels services were cancelled. After a period of time a rake of sleeper coaches appeared gingerly out of Abbeyhill tunnel, with this 92 on the far end.

    [​IMG]
     
  29. theironroad

    theironroad Established Member

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    Quite agree.

    Probably a good time for the thread to be locked until the raib issue their next update/report.
     
  30. big all

    big all On Moderation

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    yes then later with a fitted head off perhaps 20% or even up to 35% off wagons where the overall speed would be increased in proportion to brake force

    iff ii remember correctly the bell code in a signal box for a fully fitted freight train in the 70s was a 4+2+2 code
     
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