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Boilers & Accidents

Discussion in 'Steam Traction' started by johnofwessex, Sep 3, 2016.

  1. Jamessquared

    Jamessquared Nat Pres stalwart

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    If you think of a big engine, you might have over a ton of coal (i.e. rocks) at a temperature greater than 1200C. You need to cool that to probably below 500C to extinguish combustion; the amount of water needed to achieve that is considerable. Even were it possible, if you dumped that amount of water on a fire in a hurry, the resulting steam explosion would be comparable to the event you were trying to prevent, i.e. collapse of the crown. (There is also the point that initially you would get a producer gas reaction, i.e. steam + carbon = carbon monoxide + hydrogen, which would then explode in any excess air above the fire).

    Tom
     
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  2. Big Al

    Big Al Nat Pres stalwart Staff Member Moderator

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    Now where it should be. :)
     
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  3. torgormaig

    torgormaig Part of the furniture Friend

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    Thanks Al

    Peter
     
  4. Big Al

    Big Al Nat Pres stalwart Staff Member Moderator

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    As per the Bitterfeld explosion in 1977. Frightening and a lesson for all those people who might think that looking after a steam locomotive doesn't really need a great deal of knowledge and detailed experience of locomotives in general and the one you are on, in particular.
     
  5. Jamessquared

    Jamessquared Nat Pres stalwart

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    Having moved some threads, I think almost all of the "Bulleid slipping" thread from post 80 onwards needs moving to here, since there is a long discussion of boiler taper which is more relevant here than there.

    Tom
     
  6. Steve

    Steve Resident of Nat Pres Friend

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    If you read all the good instructional books they always tell you that you should immediately throw out the fire. However, anyone who has tied to throw out a large hot fire will tell you that it is asking the impossible. In the days of ash ballast it was much easier to smother the fire with this, one person on the ground shovelling it onto the footplate and the other person baling it onto the fire; however compacted stone ballast is not the easiest thing to shovel up. The other never mentioned point is that of self preservation. Do you stick to your post on the footplate knowing that the firebox may collapse any second or do you retire to a very safe distance?
     
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  7. LMS2968

    LMS2968 Part of the furniture

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    Indeed, Steve, hence the comment that some of the advice would be difficult to achieve. But either throwing out the fire or throwing in ballast would take quite a time, while putting the feed on was only a matter of seconds. That part made sense to me.
     
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  8. Steve

    Steve Resident of Nat Pres Friend

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    Indeed it would. However, on the few occasions when I have had to cross my fingers and sweat a lot, it has because the injectors wouldn't play ball, for whatever reason.
     
  9. torgormaig

    torgormaig Part of the furniture Friend

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    I believe that was part of the problem with Clan Line when it got into trouble. The only two occasions that I have been near locos that have dropped plugs (777 at Kirkby Thore, Aug '84 and 34092 at Ulleskelf, April '87) troublesome injectors were involved.

    An earlier point raised by @LMS2968 about knocking down the brick arch, I would imagine this would be easier to do in the days when the arch was made of bricks (they fell down often enough anyway:)) rather than the modern preference for cast concrete arches.

    I always remember that Kim Malyon used to say that the reason the LMS dropped far more plugs than the LNER was because LMS firemen used to box the fire up and then sit on their arses for miles on end while it burnt through, whereas the LNER discouraged this. The reason being that if both injectors failed you had no chance of getting rid of a boxed up fire, whereas you have a chance of dealing with a thinner fire before things get critical. How true this was I do not know - Kim had many such pearls of wisdom - but you can see where he was coming from.

    Peter
     
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  10. LMS2968

    LMS2968 Part of the furniture

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    The LMS didn't encourage it either!

    It did though ease the fireman's work, and if you have about 300 miles to go, it was a help.
     
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  11. Jamessquared

    Jamessquared Nat Pres stalwart

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    I'm glad it's not just me that has worried about the actual practicalities ...

    I've only ever had to throw out one fire "in anger", when a visiting engine developed a leaking tube. Fortuantely water level never got low and the injectors were perfectly able to keep on top of the water supply, but we threw the fire out as a precaution. That was only a small engine, but even so, after a half a dozen or more shovels full, the slice was starting to get uncomfortably hot; and not long after the end was getting decidedly distorted out of shape where it was melting in the heat of the fire - and that was a small loco with a cool fire, not a fire that had been working at high output for a period. In practice we had to alternate between two slices so that they could cool down; otherwise fairly soon the blade would have become uselessly soft. So the prospects of having to throw out a fire on a large pacific don't bear thinking about: I'm really not sure the advice would be possible if you had also lost control of the injectors.

    As an aside, I have in front of me a hand-written notebook from a Nine Elms (LSWR) engineman, ca. 1900. It has written questions and answers which I suspect were asked of prospective engine men as part of their progression (and, seemingly, learned by rote ...)

    One of them is as follows:

    Q: How would you act if the boiler feeds failed when working a train?
    A: I would damp down the fire with ballast and water if necessary, and place a damper on top of the chimney to check the draught, and would endeavour to find out the cause of failure by examining the water ways and injectors as far as practicable.
    Then later is what could possibly be notes of an actual exam, in which the same basic steps are drawn out ion a series of questions. So ballasting the fire was a recommended procedure, but that is on locos with probably around 15 sq ft of grate, not 50 ...

    (Old footplate joke: Q "What steps do you take if the crown is uncovered?" A: "Bloody large ones")

    Tom
     
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  12. Johnb

    Johnb Nat Pres stalwart

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    I assume that with an engine with a rocking grate the solution is to drop the whole lot into the ashpan or am I wrong? I know it wouldn’t do the ashpan a lot of good but cheaper than a new firebox
     
    Last edited: Jun 18, 2020
  13. Gareth

    Gareth New Member

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    I know Western locos have pep pipes on the footpate, but I've never noticed them on other locos, do locos from the rest of the big 4/Br have them ? Do these use the injector for their water feed or could they be used in an emergency to dampen the fire ?
     
  14. LMS2968

    LMS2968 Part of the furniture

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    All engines have these pipes but under various names - I know them as slaking pipes - to clean down the footplate, damp down dust in the tender, etc., but the amount of water delivered would make no impression on a big fire, and I personally would not want to stand in front of an open firehole door and spray water through it. And yes, they work off the injector on the fireman's side.
     
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  15. LMS2968

    LMS2968 Part of the furniture

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    I don't know if this has appeared on here before, but
     
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  16. Jamessquared

    Jamessquared Nat Pres stalwart

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    Slacker pipes we call them - I'd never thought of the etymological connection to slaking ...

    (Piss pipe is another "informal" phrase used - which probably gives a rough idea of the effectiveness of directing one at a Merchant Navy-sized grate!)

    Tom
     
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  17. torgormaig

    torgormaig Part of the furniture Friend

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    Not on Eastern engines they don't:(. There the take is off the drivers side injector, apparently to encourage lazy firemen like myself to use the other injector once in a while.

    Peter
     
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  18. peckett

    peckett Member

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    I had a plug go on a small engine ,grate area about Ten SQ/FT ,that was the result of a bad bout of priming going up a very steep grade. The water was bobbing about in the bottom nut at the time. In reflection I should have stopped with the regulator still open a small amount ,the water level drops when the regulator is closed completely ,that may have saved the day. The fire was out in a mater of minuets ,I don't think I bothered to put the injector on .Just the hand brake to stop rolling back . No damage was done to the firebox on examining in the shed.
    When all had cooled down I nipped in the firebox and removed the offending plug. Took it down to the blacksmiths shop ,he melted some lead down in a small ladle ,placed the plug on his anvil, making sure he warmed the anvil top with a blow torch, he then refilled the plug. I said warming the anvil top first because the first time I ever saw this done the anvil top wasn't warmed ,and as soon as the molten lead hit the cold anvil it shot up in the air six or eight foot .I've never seen men move so fast in my life as white hot lead rained down ,no injuries luckily.
    The engine was lite up the next day and it was soon apparent all was not well, the bout of priming had broken a couple of piston rings on the right hand side. A much bigger job.!
     
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  19. fergusmacg

    fergusmacg Resident of Nat Pres

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    Very possibly, dropping the fire into the ashpan may seam like a good idea but the same heat source (the fire) is still able to pass the heat into the boiler, if you have hopper doors and a pit perhaps you can move the engine away once dropped, in the mean time by rocking the grate and dropping it downwards you may well enliven the fire and produce more heat - do you really want to do that in that position? I was taught to use the smother the fire option as Tom mentioned, but never had to do it anger.

    I suppose there is the other option when asked what steps to take in such a situation . . . . . . bl**dy big ones!
     
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  20. Steve

    Steve Resident of Nat Pres Friend

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    Try doing that today and the HSE/ORR would be down on you like a ton of bricks but that was how things were once upon a time.
    It is a golden rule that, before pouring white metal, lead or any other molten metal that whatever is being poured into is heated to at least 105°C. In mining, it was actually a legal requirement to do so in the UK. The reason for this is to drive off any moisture that might be present. If there is even the slightest trace of dampness, it will immediately flash off into steam and, as steam is some 1600 times greater in volume than the equivalent mass of water you get an immediate explosion. I've seen it happen just once and it was not a pleasant experience.
     
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