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Post by Deleted on Jan 7, 2019 8:24:57 GMT
I saw this on FB this morning, looks like blowback to me but others have said it's just firelight reflecting off the steam? I'm not so sure about that. If it is blowback I hope no one was hurt.
The date stamped for this is 23th Dec
Pete
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Post by delaplume on Jan 7, 2019 10:54:03 GMT
Hi Pete, WoW !!.... firelight reflecting off the exhaust steam doesn't glow actually inside the cab !!..........Go to full-size screen and look at 0.06.. You can clearly see the difference in the red colour along the length of the flame, with it being much brighter nearest the firebox.. Going in reverse from 0.06 it appears to start just after they exit that low, overhead bridge.........If they were coasting through ( albeit at a fast line speed ) linked up to say 20% or less...and the regulator just cracked open, then there is not much actual blast coming out of the chimney.....Now pass under a low-slung bridge and the conditions are ripe for an induced blow-back ie not caused by burning volatiles seeking the shortest way out, but by a temp restriction of the chimney ---- in this case that bridge.. Keep going in reverse and you can see that in their approach to the bridge the exhaust was clear and no flames etc showing..... The Fireman should have put his blower on to help prevent this happening.......... This was hammered home to us on my Firing Course at the SVR......Tunnels, Bridges, even some close embankments or cuttings can induce a temp. blow back and the footplate crew must be constantly aware of their location and possible causes of blowbacks... Now imagine that same thing happening in the Boiler Room on a ship ??.......Men were literally roasted to death in some extreme cases in the days when steam ships had what's known as a "Closed stokehold".....and hand firing was still in use.. Air for the Furnace was sourced from the Boiler Room itself-----to do this the whole room was sealed and the air pressurized to approx 10 psi ( I think )....Access was via a hermetically sealed , interlocked twin-door device...On a Warship this proved to be the Achilles Heel because if the sealing was compromised the flamepath in the Furnace would reverse direction and come out of the Furnace front !! Have a read of this and refresh your memory, Pete ----------> modeleng.proboards.com/thread/9169/causes-engine-blowbacks |
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Post by Deleted on Jan 7, 2019 11:32:19 GMT
Thanks, Alan, yes I even posted in that thread...I wasn't convinced by the fire reflecting in the steam either. The end of the video shows a 'slow mo' and looks pretty grim in that cab, I can't see any of the crew? Possible that the driver is forced up close to the backhead and fireman has ducked... hope no one was hurt although looking at how large a blowback is seen and the duration of it I'd think it would be a miracle that no one was hurt? There's been nothing reported as far as I know so hopefully they got away with it.
Pete
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Post by delaplume on Jan 7, 2019 15:16:59 GMT
Thanks, Alan, yes I even posted in that thread...I wasn't convinced by the fire reflecting in the steam either. The end of the video shows a 'slow mo' and looks pretty grim in that cab, I can't see any of the crew? Possible that the driver is forced up close to the backhead and fireman has ducked... hope no one was hurt although looking at how large a blowback is seen and the duration of it I'd think it would be a miracle that no one was hurt? There's been nothing reported as far as I know so hopefully they got away with it. Pete What I forgot to add in my earlier reply is that the firehole door or flap has to be open as well......A blowback will last only as long as the prevailing conditions that caused it do, after which it ceases..........Looking at the video again, from the moment the chimney is directly under the bridge until the cab is opposite the camera is approx 2 seconds..........That's the actual blowback happening ( no prior warning etc....it's just a sudden "BANG" with roaring flame coming out of the firehole... Now, 2 seconds later and the prevailing conditions have gone ( No restriction over the chimney ) and the blowback ceases just as suddenly as it appeared....From 0.06 through to 0.09 and yes, I'd say that is reflections off the steam overhead.....My guess is that the crew are still dazed by that sudden happening and the firehole doors are still open....hence the reflection.. What's more of immediate concern is the behavior of the people on the "up" platform in regards to the yellow line etc....especially the chap in the yellow jacket who just clears away in the nick of time.... Then there are those on the "down" platform who we see after the train-- and its, exhaust --- have cleared......Yes, there they are completely off the ramp and effectively on the track-bed, just to get that "Master shot" !!.......... I'll bet that the crew will be using a much stronger Biological powder in their next wash !! I sincerely hope that I'm completely wrong, that it never happened and no one was hurt in any way...... But... |
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pault
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Post by pault on Jan 7, 2019 20:31:40 GMT
Personally I don't think it is a blow back. I think it is a trick of the lighteither from the loco fire, unlikely or the lighting on the station. Remember ther is normally an A3 has the rubber sheet between loco and tender so the flames would have to pick round the sides. For the flames to be reaching that high above the cab the cab would be a bad place to be, especially with 4 people on the foot plate. If there has been a blow back I would expect them to shut off and stop to investigate even if there were no injuries. It's not only bad enginmanship that causes blow backs, smoke box door not being shut properly or coming loose, displaced spark arrester or self cleaning screen, main steam pipe failure can also cause a blow back. Also nothing from RAIB
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jma1009
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Post by jma1009 on Jan 7, 2019 20:32:30 GMT
Hi Pete,
I also agree it looks like a very dangerous and frightening blowback.
Nothing has been reported on Nat Pres forum, and it is the sort of incident one would expect to be reported to the RAIB.
Cheers,
Julian
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Post by Deleted on Jan 7, 2019 21:01:56 GMT
I'm not so sure about that Paul, as Alan states if you trace it back to as the loco passes under the bridge you just get the first hint of the fire colour before the camera pans around to follow the train. When watching the slow-mo that doesn't look like a trick of the light to me, that looks like full flames being forced out either side of the cab, mostly to the far side, it looks pretty fiery in that cab to me?
Pete
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mbrown
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Post by mbrown on Jan 7, 2019 21:28:59 GMT
I would expect a blowback on the (apparent) scale of that one to be, not only reported, but to be common knowledge within a very short time of it happening.
But like Paul, I am not wholly convinced it is a blowback - the "flames" appear to be hovering over the cab roof and the flexible connection to the tender - whereas a blowback would have sent flames either through the rubber connection or around its sides. But whether the fire light etc can really play tricks like that, I just don't know. It does look like a fairly wet day and reflections off the steam can play funny tricks when there is a lot of moisture in the air.
Malcolm
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Post by dhamblin on Jan 7, 2019 21:50:03 GMT
If the firehole door is open, perhaps it's the glow on the fireman's overalls. It is the position they would be standing in to shovel coal.
Spectacular sequence none the less.
Regards,
Dan
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jma1009
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Post by jma1009 on Jan 7, 2019 22:00:08 GMT
Well, I've now posted the link on Nat Pres so that should get a response from others!
I can clearly see flames emitting above the cab roof that is most alarming. That is a blowback!
Cheers,
Julian
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jma1009
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Post by jma1009 on Jan 7, 2019 23:27:56 GMT
Ok, time to eat my greasetop hat again! A well known and highly respected Nat Pres member has posted the following (jump to 1 minute in) of Tangmere www.youtube.com/watch?time_continue=80&v=I8-lXdMK5qUA very peculiar visual effect to my mind, but I am suitably proved wrong by the experts, and the relevant Nat Pres forum member is definitely an expert. Cheers, Julian |
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Post by Deleted on Jan 7, 2019 23:44:37 GMT
Ok, time to eat my greasetop hat again! A well known and highly respected Nat Pres member has posted the following (jump to 1 minute in) of Tangmere www.youtube.com/watch?time_continue=80&v=I8-lXdMK5qUA very peculiar visual effect to my mind, but I am suitably proved wrong by the experts, and the relevant Nat Pres forum member is definitely an expert. Cheers, Julian me too Julian....it's quite a sight, isn't it?... I concede, Paul wins...  Pete |
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Post by delaplume on Jan 8, 2019 2:13:52 GMT
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Post by delaplume on Jan 8, 2019 2:30:19 GMT
I hope this photo comes out ok.........Been having problems with "IMG free" just lately------------>  |
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pault
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Post by pault on Jan 8, 2019 19:49:27 GMT
Sometimes it's not over when the blowback is over, there have been cases where the blowback is big enough and long enough to set light to the coal in the tender.
One night coming back from Poznan (Poland) on an OL49 we had a blowback. The Ajax firehole doors were shut but they have a number of 2"ish holes in them. Due to a mix up the blower was not put on when the regulator was shut. Next thing was we had 3' long flames coming out of the holes. We also had flames licking out round the edge of the door. Putting the blower on sorted the blowback.
That wasn't the end of it though. The cab was full of smoke and flames were coming out of the firebox cladding round wash out plugs and the gauge glass fittings. The insulation on the backhead was burning inside the lagging sheets. We then ended up having to use the slacking hose to put that out. Meanwhile the driver was hanging way out of the cab window trying to see the next station.
A small point on backhead design on this loco the blower valve was fairly high above the firehole door. Look at some of the LMS locos the blower valve is just above the firehole door. A most excellent place to put it in the event of a blowback. I guess that's one reason why they put the blower valve on the drivers pedestal on the BR Std's
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oldnorton
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5" gauge LMS enthusiast
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Post by oldnorton on Jan 8, 2019 20:17:15 GMT
What about a discharge corona from those overhead lines into a highly conductive steam cloud?
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Post by silverfox on Jan 8, 2019 23:44:57 GMT
I have somewhere a video of a GWR loco leaving Reading at night. Due to he convertible' type cab they have. there is a lovely display similar to that of Tangmere and Scotsman
As i have 52 hours of tape to get through it may be a week or two to put it up
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Post by delaplume on Jan 9, 2019 0:08:05 GMT
During my time at the SVR I was lucky enough to make the acquaintance of a budding Railway Artist by the name of John Austin......Now I think you people would agree with me that any artist, especially a successful commercial one, needs to have a very good eye for detail ?? I have Johns book and remembered that he does some particularly effective night scenes with the loco's fire "underglow" on the steam exhaust being a specialty....... From his website here are 3 that speak for themselves}---------->    |
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Post by doubletop on Jan 14, 2019 4:34:12 GMT
Well, I've now posted the link on Nat Pres so that should get a response from others! I can clearly see flames emitting above the cab roof that is most alarming. That is a blowback! Cheers, Julian I went over to the link Julian provided and some of them seemed to get a bit precious about what seemed to be a prefectly resonable question. Pete |
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jma1009
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Post by jma1009 on Jan 14, 2019 22:30:27 GMT
Hi Pete,
Yes, I don't know what all the fuss was on Nat Pres, and the thread was very quickly locked!
Cheers,
Julian
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