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To airbrake or not?

Discussion in 'National Railway Museum' started by southyorkshireman, May 8, 2008.

  1. southyorkshireman

    southyorkshireman New Member

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    As it has been debated on here already, is there any hard and fast ruling about which mainline registered NRM loco's gain air braking and which don't? Is it to an extent down to the group overhauling the loco?

    As it stands, I believe 4771 retained its vac system but had a through air pipe.

    850 has train air brakes
    777 and 70013 are vac only and have no through air pipe as far as I am aware

    Scotsman I assume will retain its full air system?

    Incidentally, was it intended for 13 to have air brakes fitted as this is referred to in the NRM's own famous loco's series of books
     
  2. Anthony Coulls

    Anthony Coulls Member

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    I will talk to my colleagues next week, but it's probably fair to say that we would not have fitted air brakes to Scotsman if it hadn't already got one. Through piping is the answer as we can then use 47 798 as a Thunderbird. As I say, that's the Thursday night thoughts, but will get the official word as soon as I can.
     
  3. Jacobite

    Jacobite New Member

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    To airbrake or not? quite simply put, the answer has to be yes. If you are to have any hope of the locomotive in question operateing mainline with as many toc's as possible.

    EWS operate in air only (I believe this to be a business decision, as they still have vac on their safety case and indeed, the drivers are still expected to keep up competencies on vac brakes. can anyone confirm?)

    WCRC operate both.

    So if you only have vac fitted then you are expecting to operate only with WCRC.

    Conclusion - fit both and keep your options open!
     
  4. Alex

    Alex New Member

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    Hi

    I think its the way to go, if you were to fail on the mainline having air brakes would atleast mean that your could be rescued by any diesel loco.

    Alex
     
  5. Kerosene Castle

    Kerosene Castle New Member

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    I'm surprised at that, but having had a look at some pics of 777 it would appear to be correct. They may not have got round to it yet with 70013.

    I thought though that a through pipe with dump valve was compulsory, or is that just with EWS? Of course they don't use vac any more, but 5051 had to have one even when they did.
     
  6. southyorkshireman

    southyorkshireman New Member

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    Another silly hypothetical thought to add to variety

    what about making all railtour stock for steam air or dual braked (therefore mk1s only, or air braked mk2s bye bye TY01 and Green train) and through piping vac only locos, but fitting a relay valve (assume it is just a through pipe on such fitted locos at the moment?), therefore if the ejector is capable of operating, the loco can still be braked. This would obviously place the costs onto the rolling stick providers, but as the stock sees more use perhaps this would work out better in the long run? and saves engineering nightmares for loco owners, whilst ensuring any air braked diesel available could assist.

    Of course only academic
     
  7. craiggluyas

    craiggluyas New Member

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    Why is it not possible to do what we do on the 15" gauge, and pipe the loco with a brake valve but house a diesel driven compressor in the support coach? This would only require the same work as piped only.....
     
  8. Sidmouth

    Sidmouth Part of the furniture Staff Member Moderator

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    La La land sadly although eminently reasonable or should we nationalise railtour operators ?

    Thing is the current system kind of works
     
  9. southyorkshireman

    southyorkshireman New Member

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    Oh I agree it works, and doubt there will be any change to that (except maybe vac trains going someday, who knows?)
     
  10. Kerosene Castle

    Kerosene Castle New Member

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    This is essentially what was done to Pendennis Castle when it was out in Oz. The water carrier that ran with the engine was fitted with a silenced compressor and proportional valve - really it's just an adaptation of the system used on 5029/6024 etc. The engine remained straight vac, but with a through air pipe & emergency brake valve.

    The GWS has enquired into seeing whether such a system would be feasible over here, using the support coach, but Notwork Rail or whoever threw the inevitable hissy-fit, basically because the system is spread over 2 vehicles. If they were permanently coupled, it's a different matter.

    The fact that this system has worked perfectly well for a number of years on several engines in Oz is apparently neither here nor there. But then this is 21st century Britain we're talking about. If enough people got together and all threw money into the pot to get it type approved, then perhaps something could happen.
     
  11. Man of Kent

    Man of Kent New Member

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    When first fitted with an air pump in the overhaul that finished in the mid 90s, Clan Line had the pump in a recess in the rear of the tender, which was concealed with doors. I guess this would cut into the water space, but I suppose that isn't such a problem on a Bulleid with their higher capacity to start with.

    I have no idea whenther the air pump is still there or whether it is now on the engine like other Bulleids.
     
  12. Dan Hamblin

    Dan Hamblin New Member

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    Still there.

    Regards,

    Dan
     
  13. southyorkshireman

    southyorkshireman New Member

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    Last I saw it every beat, a stream of steam shot up out the back of the tender. Is that intentional as an exhaust or a leak?
     
  14. Mike Turner

    Mike Turner New Member

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    It's the exhaust - we don't have leaks (well, not many, anyway).
     
  15. Jacobite

    Jacobite New Member

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    To correct my earlier statement, I've been told that EWS operate in air only these days as they no longer have the ability to rescue a vac braked train. ie all the diesels operate in air and that if a vac braked steam charter was to fail they would be unable to rescue it!
     
  16. std tank

    std tank Member

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    Time to send for Riley International Rescue in that case.
     
  17. James Shuttleworth

    James Shuttleworth New Member

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    May I debunk a few urban myths, about air-braking, before they become accepted as fact?

    In simple terms, there is no mandatory requirement for the air-braked operation of steam-hauled trains (and remember, in the main, we are talking about air-operated train brake control, not the brakes on the locomotives themselves, which remain either vacuum or steam - with, of course, certain notable exceptions); under the speeds and conditions operated, both air- and vacuum-braked are virtually as efficient as each other, so there is no safety issue and this is unlikely to change. The 'problem' relates to supply of rolling stock, competency and recovery.

    Of the remaining Mk1 vehicles, some are vacuum only (only WCR), some are air only and some are dual-braked. Of the Mk2s, they are either vacuum only (Vintage Trains and the WCR 'Green' set) or air only (eg. WCR 'Cambrian' set, VSOE Pullman and all air-cons). Regulations dictate that a barrier vehicle is kept at the rear of train comprising of Mk1 stock, ie. a Mk2 vehicle or non-passenger Mk1. It is probably true to say, therefore, that air-braking appears to offer greater flexibility, operationally, particularly as most (but not all) diesel locomotives are air-braked and any loco change would probably require an brake change-over.

    Since the withdrawal of the last vacuum-braked ballast wagons, six or so years ago, EWS has been an 'all air' operator, although, in reality, before then, many of their remaining nominally dual-braked diesels (such as the former Res 47s) operated in air-only condition; apart from private-owner diesels and a handful of class 37/4s, all their 'home' fleet of Class 66s and 67s are air only. Upkeep of their drivers' vacuum-braked competency would, therefore, be difficult and understandably disproportionate to any business justification; even with RTC's move from WCR to EWS, as its operator of choice, it will be noted that there has been no rush to re-instate vacuum competency, in order to operate locos such as 'The Great Marquess'.

    WCR's position is quite different, given the amount of regular steam operations undertaken, where it is possible to maintain this competency, although we are equally comfortable in operating air-fitted steam locos in air mode. We have also re-instated vacuum braking on several diesels, for added flexibility.

    The final point is recovery. All operators must have a recovery plan, to clear the line, in the event of train failure, which, in simple terms, in the case of steam, usually means the summoning of the nearest appropriately-braked diesel locomotive; this is relatively straight-forward for air but not necessarily so for vacuum. Vacuum-only steam locomotives are therefore usually 'through-piped' for air or carry a temporary air pipe, in order to by-pass the locomotive and recover the train in air-braked mode (assuming, of course, it is a dual-braked set of coaches). In the case of a vacuum-only set the options are either for a diesel to remain on the rear of the train or to shadow it or keep it locally on stand-by (such as in the case of the 'Shakespeares' or 'Jacobite'), given the scarcity of vacuum-braked diesel locos.

    For the steam loco owners, 'you pays your money and takes your choice'. Fitting of air-braked control systems began with 'Clan Line', in the early 90s, principally so it could operate the air-only VSOE Pullman and other locos followed suit, in the main because mixed messages, at the time, from InterCity and then Res, which suggested that they would eliminate vacuum stock and working. 15 or so years later, sufficient choice is still there for this not to be necessary. It is fair to note, however, that a significant number of steam failures have been related specifically to air brake system failures on the locos; the systems are complex and do not sit well with heat and dirt and there is a lot to be said for keeping it simple.

    James Shuttleworth
    WCR
     
  18. beetlejuice

    beetlejuice New Member

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    Thank you James for a clear concise and very Intressting post!
     
  19. southyorkshireman

    southyorkshireman New Member

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    Yes, thanks for that James, extremely interesting!
     
  20. Christopher125

    Christopher125 Member

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    Again, thankyou for your very interesting reply James.

    Chris
     

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