If you register, you can do a lot more. And become an active part of our growing community. You'll have access to hidden forums, and enjoy the ability of replying and starting conversations.

Boiler safety issues

Discussion in 'Steam Traction' started by marshall5, Jun 9, 2021.

  1. Jimc

    Jimc Part of the furniture

    Joined:
    Sep 8, 2005
    Messages:
    4,052
    Likes Received:
    4,665
    Occupation:
    Once computers, now part time writer I suppose.
    Location:
    SE England
    Heritage Railway Volunteer:
    No I do not currently volunteer
    Modern pressure gauges or the ones they had back then? If a significant cause of overpressure accidents was drivers assuming the gauge was wrong rather than the safety valves, could a factor in the lack of such incidents after Buxton be down to pressure gauges becoming more reliable and more trusted?
     
  2. LMS2968

    LMS2968 Part of the furniture

    Joined:
    Sep 1, 2006
    Messages:
    2,987
    Likes Received:
    5,084
    Gender:
    Male
    Occupation:
    Lecturer retired: Archivist of Stanier Mogul Fund
    Location:
    Wigan
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    They were Bowden gauges, same as now.
     
  3. Steve

    Steve Resident of Nat Pres Friend

    Joined:
    Oct 7, 2006
    Messages:
    11,930
    Likes Received:
    10,088
    Occupation:
    Gentleman of leisure, nowadays
    Location:
    Near Leeds
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    I've had two pressure gauges fail whilst I was on a loco and had to be changed. The first time, I noticed that the pressure was dropping somewhat rapidly on the climb to Goathland so I started to shovel a lot more, We were down to about 100 psi and I was surprised that the loco was actually still going as well as it was. Then the safety valves lifted and I realised the gauge had failed. On another occasion, the gauge started to stick at a pressure then suddenly jump to the correct pressure. I was also doing a hydraulic test back in March this year and we were using the boiler inspector's pressure gauge, freshly re-calibrated, as the reference. I seemed to be pumping for an age and it was getting harder but the gauge was still reading zero. As I was outside the cab, I couldn't see the locos own gauge but a check on the this showed that we had plenty of pressure. The inspectors gauge was then checked on our deadweight tester and just did not work.
    I've known the safety valves on a T.R. No.6 stick until helped by a well aimed smack with a shovel. That was a over 50 years ago, though, and I know maintenance standards have improved since then. I've also been on a loco without a pressure gauge, but not for long! That was at Ackton Hall colliery in about 1973. The diesel had failed and the steam loco had been pressed into service. The driver was quite happy to be using the loco without it, saying it had two safety valves so he didn't need a gauge, as well.
     
  4. Eightpot

    Eightpot Resident of Nat Pres Friend

    Joined:
    Aug 10, 2006
    Messages:
    8,077
    Likes Received:
    2,264
    Gender:
    Male
    Occupation:
    Engineer Emeritus
    Location:
    Aylesbury
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    It is common with a Sentinel boiler that if overfilled with water the safety valves only lift when the pressure rises to 20 or 30 lb above normal working pressure. Anyone with an explanation for this behaviour?
     
  5. clinker

    clinker Member

    Joined:
    Oct 8, 2016
    Messages:
    569
    Likes Received:
    348
    Gender:
    Male
    Location:
    romford
    Heritage Railway Volunteer:
    No I do not currently volunteer

    Just a guess really but could it be due to the 'Density' of the water being higher than that of steam? so water being 'Thicker' takes more pressure to force out of the valve?
     
  6. Eightpot

    Eightpot Resident of Nat Pres Friend

    Joined:
    Aug 10, 2006
    Messages:
    8,077
    Likes Received:
    2,264
    Gender:
    Male
    Occupation:
    Engineer Emeritus
    Location:
    Aylesbury
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    I believe the name is actually Bourdon.
     
  7. Steve

    Steve Resident of Nat Pres Friend

    Joined:
    Oct 7, 2006
    Messages:
    11,930
    Likes Received:
    10,088
    Occupation:
    Gentleman of leisure, nowadays
    Location:
    Near Leeds
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    I’ve never experienced that but if the boiler is overfilled the valves don’t shut until the pressure has dropped substantially.
     
    marshall5 likes this.
  8. Sheff

    Sheff Resident of Nat Pres

    Joined:
    Apr 21, 2006
    Messages:
    7,567
    Likes Received:
    2,345
    Gender:
    Male
    Occupation:
    Retired Engineer & Heritage Volunteer
    Location:
    N Warks
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    Bowden was the cable chappy.
     
  9. torgormaig

    torgormaig Part of the furniture Friend

    Joined:
    Jul 17, 2007
    Messages:
    4,440
    Likes Received:
    6,546
    Twenty plus years ago I was on the K1 one morning, going light engine to Pickering to work the first down train of the day. After Levisham I resigned myself to the fact that I had over cooked the firing and with no water space left sat back to let the loco blow off. The needle crept up to 225lbs then on to 230, 235 and 240 with still no sign of the valves wanting to lift. Puzzled, my mate said to not let it climb any further and that we would check it at Pickering. On arrival there we coupled onto the stock with the chimney to the train. Having done the brake test he destroyed the train brake and secured the loco, then gingerly opened the regulator and watched the steam chest gauge to see how far it would rise. With 240 on the pressure gauge we could only get 185 on the steam chest gauge. That being so I was instructed to keep the pressure gauge below the 250 mark, as the loco would manage the train adequately on about 190lbs. At Grosmont we retired to the shed where the duty fitter was waiting to fit a fresh gauge and in no time at all we were back on the train to work back to Pickering.
    I have never heard of a pressure gauge being checked in this manner before or since but it worked in this situation and I was mighty impressed by my mates ingenuity.

    Peter
     
  10. LMS2968

    LMS2968 Part of the furniture

    Joined:
    Sep 1, 2006
    Messages:
    2,987
    Likes Received:
    5,084
    Gender:
    Male
    Occupation:
    Lecturer retired: Archivist of Stanier Mogul Fund
    Location:
    Wigan
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    Yep! Unsure of the spelling, I started with Bowden and put it into Google - and it gave a result. Perhaps I should have read further: Bowden Gauges is a brand name.
     
  11. Jamessquared

    Jamessquared Nat Pres stalwart

    Joined:
    Mar 8, 2008
    Messages:
    26,100
    Likes Received:
    57,416
    Location:
    LBSC 215
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    Every day's a school day!

    Th oddest occurrence I can remember seeing with a pressure gauge was one day on the H class. I'd lit up in the yard but we were trapping another loco in, so the running foreman arranged for us to be propelled up to the top of the loco yard exit road by the trapped loco. At that point, we still had no steam (not being due off shed for a few hours), though the fire was well established and I was expecting steam at any moment.

    After we moved by a wheel turn or so, I noticed the pressure gauge come off the stop, which wasn't a great surprise, given where I thought I was with preparation. However, as we moved the hundred yards or so up the headshunt, the pressure kept rising, until we had about 40psi by time we stopped. Even the H class isn't that free steaming! Slightly confused, I tried the blower: immediately the fire livened up and the smoke rose straight out of the chimney. So the pressure was "real", however, in doing so it also dropped a bit. Leave the blower on, the fire livened up, and the pressure continued to drop, after a short while we were back down to zero on the gauge and the blower stopped working!

    What I believe had happened was that as the loco moved, the advancing piston drew air in behind it through the cylinder cocks; then when the piston reversed, that air was compressed and pushed the valve off the valve face, allowing some of the air (that which didn't just escape through the drain cocks) to travel "backwards" through the inlet space, steam pipe and regulator into the boiler. Withe the pressure higher in the steam pipe than the boiler, that would push the regulator valve away from its face, allowing the compressed air into the boiler; then, when the pressure in the steam pipe dropped, the valve would seat against its face and therefore that compressed air wouldn't leak away again from the boiler.

    It was an oddity, nonetheless!

    Tom
     
    Richard Roper, 2392, 35B and 2 others like this.
  12. torgormaig

    torgormaig Part of the furniture Friend

    Joined:
    Jul 17, 2007
    Messages:
    4,440
    Likes Received:
    6,546
    That reminds me of the occasion that we shunted the LMS 2-6-4T, No. 2500, round from the NRM's South Yard to the Main Hall (North Yard) after the LMS event in 2011. It covered a distance of two miles plus and by the time we stopped in the station on our way through we had 40lbs on the clock. It was enough to blow the whistle, albeit somewhat feebly:).

    Equally feeble is the excuse to show a picture of the loco in Platform 9 at York on that occasion.
    mini_IMG_4584.jpg

    Peter
     
    mcjlf1, Richard Roper, 2392 and 6 others like this.
  13. LMS2968

    LMS2968 Part of the furniture

    Joined:
    Sep 1, 2006
    Messages:
    2,987
    Likes Received:
    5,084
    Gender:
    Male
    Occupation:
    Lecturer retired: Archivist of Stanier Mogul Fund
    Location:
    Wigan
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    The nearest I got to this was on the Severn Valley, and the 2-10-0 'Gordon' was being steamed for the first time since it arrived. The fire was lit on Saturday morning, and by Sunday evening the pressure gauge hadn't moved, despite the amount of blazing wood in - and protruding from - the firebox.
    In desperation, it was decided to propel the engine through the station a couple of times to fill the boiler with air, as described. The loco chosen for the move was 'The Lady Armadale', with me as fireman. Being evening, I'd run the fire down, so then had to bring it up again. 'The Lady A' did the job with two return runs through the station. This gave 25 p.s.i. on the gauge, sufficient to get the jet working, and so steam was made.

    I never fired 'Gordon', something I don't regret, but I understand it was always a pig to raise steam from cold.
     
    Bluenosejohn and Jamessquared like this.
  14. MellishR

    MellishR Resident of Nat Pres Friend

    Joined:
    Apr 16, 2009
    Messages:
    8,068
    Likes Received:
    5,164
    Tom's account makes sense but the similar story with the LMS tank is more puzzling, because that loco has piston valves. If those were in mid-gear they would surely not pump any air into the boiler. Even if it was set in forward or backward gear, wouldn't that result in pumping air into the boiler when travelling in one direction and out when travelling in the other direction? Or might someone have cunningly re-adjusted the reverser during the shunting so as to keep pumping air in?

    Edit: as in LMS2968's story.
     
  15. LMS2968

    LMS2968 Part of the furniture

    Joined:
    Sep 1, 2006
    Messages:
    2,987
    Likes Received:
    5,084
    Gender:
    Male
    Occupation:
    Lecturer retired: Archivist of Stanier Mogul Fund
    Location:
    Wigan
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    You have to set the gear to suit the direction of travel, The was someone - actually, a crowd - on the footplate.
     
  16. LMS2968

    LMS2968 Part of the furniture

    Joined:
    Sep 1, 2006
    Messages:
    2,987
    Likes Received:
    5,084
    Gender:
    Male
    Occupation:
    Lecturer retired: Archivist of Stanier Mogul Fund
    Location:
    Wigan
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    Looks well hauling the Coronation Scot bunker first!
     
    Richard Roper likes this.
  17. MellishR

    MellishR Resident of Nat Pres Friend

    Joined:
    Apr 16, 2009
    Messages:
    8,068
    Likes Received:
    5,164
    If you set the gear as normal for the direction of travel, wouldn't that pump air out of the boiler?
     
  18. torgormaig

    torgormaig Part of the furniture Friend

    Joined:
    Jul 17, 2007
    Messages:
    4,440
    Likes Received:
    6,546
    I was on the loco but after 10 years I have no recollection if the gear was moved to suit the direction of travel or not. I suspect that actual mid-gear may not have coinsided exactly with what was shown on the reverser.
    Waiting to bank the train out of Euston?:)

    Peter
     
    LMS2968 likes this.
  19. LMS2968

    LMS2968 Part of the furniture

    Joined:
    Sep 1, 2006
    Messages:
    2,987
    Likes Received:
    5,084
    Gender:
    Male
    Occupation:
    Lecturer retired: Archivist of Stanier Mogul Fund
    Location:
    Wigan
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    I didn't say 'as normal', I said 'to suit', i.e. the opposite way. The cylinders then act as an air pump. As the piston moves away from the port open to exhaust, it draws air down the blastpipe. At the end of the stroke, the port is open to admission, and the air is pushed through it to the main steam pipe and thus to a partly opened regulator and into the boiler, where pressure is created.

    It's a false pressure though: if you use it it drops rapidly, as Tom said, since there is no water being evaporated to steam to replace it, but it's enough to work the blower for a while, get heat flowing through the tubes, and raise a pound or two of steam, which can then work the jet to raise further steam

    It works. Tom, Torgormaig and I have all seen it in action, accidentally in the first two cases but definitely by design on the SVR
     
    MellishR, Richard Roper, 2392 and 3 others like this.
  20. marshall5

    marshall5 Well-Known Member

    Joined:
    Oct 26, 2010
    Messages:
    2,375
    Likes Received:
    3,981
    Location:
    i.o.m
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    Unlike on a loco, when driving a traction engine most of the braking is done on the reverser. Going down a steep hill, with the reverser back beyond mid-gear there is a tendency to pump air into the boiler and it is/was known for the safety valves to lift because of it. The old drivers use to say that the air was injurious to the gland packings but I tend to think that it was the heat generated as one would see the oil smoking on the cylinder block. My old engine was a compound with good bores and rings so holding the reverser between notch 3 and mid-gear with the band brake screwed down was usually sufficient to hold it back. If things were getting a bit smoky down the front end I would open the taps for a little while. Although I'd driven railway locos plenty of times I nearly scared myself $hitless the first time I took a traction engine out on the road!
    Ray.
     
    Richard Roper, clinker, jnc and 5 others like this.

Share This Page