34053 SIR KEITH PARK GETS STUCK ON 'DEAD CENTRE'
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- Опубліковано 5 вер 2024
- On August 29th 2017 my wife and I alighted at Hampton Loade and paused to watch 34053 depart. Due to the loco stopping on 'dead centre' this departure took three and a half minutes. The young driver had to set back twice before the Pacific loco got away.
The chief engineer on 34081 92 Squadron told me that it is not uncommon on Bulleids. Theirs, an original, has done it a couple of times. It also happened, to a lesser degree, to Caprotti Standard 5 No. 73129, see 2-47 • 73129 makes loud noise...
As the same old comments keep cropping up although fully covered below I include here the definitive explanation posted by an experienced driver of these locos:
"If the valve timing is slightly out, one cylinder can be past the point of cut off (i.e. no steam being admitted), and of the remaining two cylinders, one can just be coming on to lead (Steam that is admitted prior to the piston reaching the end of it's stroke in order to cushion the deceleration and reversal of the piston) while the other is on the admission part of the stroke, meaning that one cylinder has no steam going to it, while the other two are fighting each other. Putting the engine into the other direction can move the valves such that you will end up with two cylinders working the same way as each other (All be it the wrong way) and allow you to move the loco slightly to re-set the valves.
"I did have one occasion on this loco where I set back a couple of feet, stopped, then couldn't get her to move either way, it took a little while before I realised that upon stopping her, I had automatically clipped up the steam brake while altering the reverser, in order to hold the loco still, and had forgotten to release it, with the effect that I, having got her off of centres, was now trying to take off with the brakes on!"
For another loco in trouble see: • A STEAM LOCOMOTIVE IN ...
For a review of Bulleid Pacifics see: • O.V.S. BULLEID PACIFIC...
For Sir Keith's last months on the Severn Valley see:
• SIR KEITH PARK'S LAST ...
For a Standard 5 loco in a similar situation see: • STANDARD 5 No.73129 HA...
Sir keith park is a name familiar to me as I was living and working in Auckland when he died in 1975 .Air Chief Marshal Sir Keith Rodney Park, GCB, KBE, MC & Bar, DFC (15 June 1892 - 6 February 1975) was a New Zealand soldier(an ANZAC survivor from gallipoli, First World War flying ace and Second World War Royal Air Force commander. He was in operational command during two of the most significant air battles in the European theatre in the Second World War, helping to win the Battle of Britain and the Battle of Malta. In Germany, he was supposedly known as "the Defender of London.And nice that his name is remembered on a 4-6-2 Pacific as the design was first Conceived in New Zealand and built for the NZR by Baldwins in the USA .
A great man who had a terrible time from Bader and Leigh Mallory. Absolutely a hero
If the valve timing is slightly out, one cylinder can be past the point of cut off (i.e. no steam being admitted), and of the remaining two cylinders, one can just be coming on to lead (Steam that is admitted prior to the piston reaching the end of it's stroke in order to cushion the deceleration and reversal of the piston) while the other is on the admission part of the stroke, meaning that one cylinder has no steam going to it, while the other two are fighting each other. Putting the engine into the other direction can move the valves such that you will end up with two cylinders working the same way as each other (All be it the wrong way) and allow you to move the loco slightly to re-set the valves.
I did have one occasion on this loco where I set back a couple of feet, stopped, then couldn't get her to move either way, it took a little while before I realised that upon stopping her, I had automatically clipped up the steam brake while altering the reverser, in order to hold the loco still, and had forgotten to release it, with the effect that I, having got her off of centres, was now trying to take off with the brakes on!
Many thanks Olly. At last we have a definitive answer. Regards Alan
No problem, hope everyone was able to follow it.
Another thing people seem to have forgotten in some of these comments is that steam loco's have double acting cylinders, so unlike a car, the piston is driven in both directions.
I remember seeing Sir Keith Park at Dairycoates in Hull still in ex-Barry state and wiping the crud off the cab roof to discover the original malachite green paint. What a wonderful transformation. Even the ex BCB Barony Colliery Barclay 0-4-0ST NCB No8 that stood close by has been restored.
It's amazing what time, money and enthusiasm can achieve.
NJPurling I remember when I was younger making the smoke deflectors and running gear at Cambells them smoke detectors about 12ft long certainly no small piece of sheet metal then had to edge it as well. I have a photo somewhere of myself next to sir kieth at dairycoates in my drainpipe trousers and baisn haircut 😵🤣😂
Fair play to the young driver
Alan, having read all the comments and suggestions, particularly the points noted by Rosie2857, I think we have probably concluded why this happens - and it does indeed seem to happen more frequently than simple mechanics would suggest, and with crews of all ages and levels of experience. There must be several stopping positions where the combinations of inlet valve lead, cut-off and crank angles conspire to create very low net starting torque, insufficient to move the train. Whatever the reason, your footage has certainly sparked a debate, and I for one have learned something from it. Thank you!
Little did I think, when videoing SKP leaving, that it would lead to such an interesting exchange. Thanks for your input. Warm regards Alan
(PH) You've renamed me :-) I'm a fleet-footed Grange, loved by all, not a filthy squat low-geared freight-heaver. 6857 is Tudor Grange and Rosie is what I got called at work. My real name is Tudor Hughes, a Londoner of Welsh extraction.
I'm glad we've sorted out this apparent contradiction, that 3-cyl locos need to set back more often than 2-cyl ones. I seem to remember reading something about it in a Railway Magazine in the 50's. Yes, I'm quite old (74).
Fascinating! I honestly didn't know it was possible for a 3-cylinder simple to stick at tdc!
Especially when you consider there are effectively six cylinders as each cylinder is bi-directional.
Bless her ! just having a bad day like we all do sometimes :o) thanks for posting .
instablaster...
Cabbed this loco at the Bluebell shortly after it had been restored ... Amazing... Driver & Fireman allowed me & a couple of kids to experience the footplate... great memory
I witnessed this happening again to this loco at the Llangollen steam gala Oct 2017
Interesting. Thanks for letting me know.
It was quite common at Basingstoke for Bulleid drivers to 'set back' a bit before starting. It usually avoided the dreaded wheelspin. Never saw one jam up completely, though.
I have the same problem with my kettle when the thermostat gets stuck.
What a refreshing change for the comments and replies to be as informative as the video itself! Definitely a case of being in the right place at the right time, Alan, and perhaps even '(please) don't shoot the messenger'. I'm glad for the sake of the 'young driver' that it happened again with a different crew. Was the whistle near the end an obligatory one or a delightful indication of defiance? I wish my videos captured this level of genuine interest! Kind regards, Bob.
Thanks Bob. It was one of those strokes of good fortune. We hadn't time to join the southbound train at Bridgnorth so did so at Hampton. On alighting at Hampton on our return the platform was empty so I quickly set up the camera for a three quarter rear departure shot and the rest is history as they say. Incidentally, I read that the mighty Clan Line 'stuck' for 8 minutes at Sherborne on July 9th!
This is one reason you are taught at improvement to never get stuck in top dead centre if I was the driver I would put it in reverse
After chatting with knowlegeable friends today, my thoughts are that if the driver had left the valve gear 'linked up' when he tried to start off forwards, it's possible that the steam ports to all three cylinders could have been closed. The fact that he had to reverse - twice - also hints at there being some sort of valve timing issue. However, I'm told that this class of loco 'does this sort of thing'!
Thank you for your thoughts Phil which I'm sure are on the right lines. However, I don't believe that the driver caused it to happen, for two reasons:
1. The reverser appears to be in full forward.
2. I visited Hampton Loade this evening, two days later, and with a different crew the same thing happened, although not so prolonged.
It has been suggested that this engine is set to have slightly lower max cutoff.
Uh, I thought the purpose of "adjustible" valve drive gear is to be able to very "cutoff" so it's not fixed with a constant "timing".
@@deeremeyer1749 it cuts of the supply of steam to each cylinder earlier, but the valves are always at 120 degrees to each other, altering the cut off makes no difference in a situation like this. The most likely cause here is one cylinder on dead centre with one of the remaining two just comming onto lead with the other on admission, with the reg blowing slightly (which from memory, it was at the time) the results are obvious
Damn that's unlucky getting a 3 cylinder loco centered!
The chief engineer on 34081 92 Squadron told me that it is not uncommon on Bulleids. Theirs, an original, has done it a couple of times.
I would have thought that was near enough impossible
@@arthurrytis6010 insanely difficult, but not impossible.
We always left our double beat reciprocating pumps at end of stroke
Nice video and fun to watch. Take care now.
Thank you. A lucky case of right place, right time.
Sir Keith would hot have been amused !
How embarrassing! Good job there was a bit of a gradient.
Noel
Strangely enough he can set back with steam, no gravity required. Alan
I had to read it twice but now it makes sense to me.
This is a 3 cilinder loco.
As said,
1 piston is on dead center, you can admid steam, but nothing Will happen.
1 piston is at the point where the admission of steam stops by the valve Gear (approx 60% cutoff?)
so this piston will not any work.
1 piston was going tot dead center, steam is admidded by the valve gear to form a cussion to slow down the piston, which is a counter action to the first piston.
I understand that to a slight fault in the valve gear setting this could happen.
A 2 cilinder locomotive is less sensitive to these errors i think.
One ex driver has said that the Standard Class 4 Moguls, 76XXX which had two cylinders, were prone to the problem.
Parsound , does this also have something to do with incorrect valve setting?
Normally 2 cilinder, 90 degrees squared "should" be able to run at all times.
...steam locomotive wheels are supposed to be "quartered" (ninety degrees out of phase from each other) for this exact reason...when the cylinder on one side is at dead center...the cylinder on the other side is at mid stroke...
True for a two cylinder engine, this one has three.
I still don't understand how it's possible to have the steam ports closed to all three cylinders at once, regardless of the position of the reversing gear. That doesn't make sense to me, given the fact that the cranks are 120 degrees apart, and the valve events are unique for each cylinder.
Although there are six drives per revolution only one of those is in its drive cycle at any one time. The number of cylinders is irrelevant. If you study the position of the coupling rod adjacent to the platform you will see that it is almost dead in line with the piston rod, ie 'dead centre'. In fact, after the first reversal it is even straighter! Thus, that cylinder is the one about to receive steam for a power stroke, the inlet ports to the other two cylinders are closed, but as it is dead centre it can't move.
No, it's not possible, provided the cutoff is long enough and the valves are set more or less correctly. The loco sounded regular enough once it got under way so the valves could not have been seriously out.
There are two rather remote possibilities in explaining this. The first is that if one crank is about 20° before dead centre the inlet port will be just open due to the lead on the valves (constant with Walschaerts) and steam will tend to push the piston backwards. Another crank will be at 100° after dead centre and the inlet about to close. (This corresponds to a cutoff of 59%). The third crank will be 40° after dead centre and ought to be enough to get the engine moving but maybe not if the first crank is opposing it. Maybe full gear on these machines is less than 75%. On Gresley locos it was 65%.
The other possibility is that with the middle cylinder inclined, it will change all the angles I've mentioned and in certain crank positions maybe make things worse.
Maybe the driver was a bit tentative with the regulator. He could have opened it full when he realised the engine was not moving but hung on to it for dear life and closed it as soon as the engine moved. Maybe that would have shifted things, as the pharmacist said to the constipated customer.
Thank you for your detailed theory with which I wouldn't dream of arguing. Incidentally. I recently read a piece by mainline driver Wayne Thompson of DB Cargo who regularly drives Clan Line. He wrote, " …Waiting to leave, [Sherbourne] then came one of those moments when a loco shows you who’s the boss! She would not move forwards or backwards. It is a strange thing with three cylinder locos, in that they can get stuck in what is termed ‘top dead centre’. You would have thought with six power strokes per revolution it wouldn’t happen, but it does. It took us around eight minutes to get her to move, then it was backwards, not by much but enough to get us going again."
It seems that 3-cyl locos are just as likely to get "stuck" as 2-cyl ones, according to some driver opinions in the Railway Magazine going back some time. (I'm 74 BTW, oh dear). This defies geometry, as others have said, until you look at it in more detail. There's also the fact that 3-cyl locos have smaller cylinders than the equivalent 2-cyl locos.
Setting back was quite common in steam days - I've even seen it on the Oxted line with locos starting 8-coach trains on 1 in 100. It seems to be a question of getting one crank in a position to give enough leverage on the axle to start the train.
I've no idea whether my theories are correct - it's the only thing I could think of and it is at least rational but I must say I was surprised at the difficulty the driver had with a fairly light train and no serious gradient. He must have been knackered after all that with winding the reverser back and forth.
I too remember many times when locos set back in steam days. (I'm 79!!) All the drivers on the SVR seem to treat the regulator with care when starting Bulleids due to their reputation. Being a GWR line they contend that Western engines don't slip but I've got considerable footage to prove, "that ain't necessarily so". I went back to Hampton for the same train the following day and she/he stuck again but only one setting back got him away.
This cannot happen. It’s a three cylinder engine . There is always a cylinder on a power stroke.as one comes of stroke the other is already on power. There is no flat spot .some comments mention lead in steam but this cannot overcome the adjacent cylinder on its power stroke. You would need to set the cut off at near mid gear for this to be an issue.
Read the earlier comments, or even the explanation in the video description, it can and obviously does happen...one of the reasons that American locomotive engineers also paid attention to where the rods where when stopping, just so they wouldn't get into this situation by accident.
It was a common and very annoying problem on Ivatt 2-6-0s but I had never heard of it on Pacifics and stranger still on a 3cylinder.
That's interesting Keith. I've not seen or heard of it happening on 43106...yet!
That's Sir Keith Park for you... A bag of Nails! The valves were always out of timing.
Nice Video!
Must admit this is not a problem I'd ever considered before. Never realised that if you stop with the valve gear wrong you can't go again.
Every day's a school day
Its even more fun with only one cylinder as the typical tractor or traction engine would have had. I find myself constantly turning the engine off the center by hand, not something you can do with a locomotive.
Single cylinder stationary engines also had to be turned off the dead center by hand in order to start. If they were too large to turn by merely grabbing the wheel, the flywheel was provided with notches for a prybar to lever the engine around to starting position. Or a smaller engine called a barring engine was provided to bring the main engine to starting position.
Nice video, subscribed
Embarassing for the loco crew! But well done on solving the problem unaided.
They performed admirably.
Water in the cylinders?
Never had that happen in my 7 years driving...hmmm
Well, SKP wasn't a well engine, one cylinder was always trying to go backwards hence why she was quite easy to get stuck on dead centre
Weird. How is that possible with a steam engine with more than one cylinder? With the 90 degree 'squaring' I thought that at least one cylinder/piston would be able to move the locomotive at all times.
/Anders
Hopefully some well informed person will enlighten us.
It sure doesn't sound like its "hitting" on more than one cylinder for one thing. Or maybe TWO if its a "three-cylinder. And if the two outside cylinders are "180 degrees" opposite the inside cylinder, it could still be "stuck on dead center".
3 cylinders so in theory the cranks are set at 120 degrees. However, not only is the inside cylinder more steeply inclined than the outside ones but is inside admission while the outside ones are outside admission. All these factors come together in a Rebuild's very uneven exhaust beat. By reversing, the driver moved her out of the dead spot.
Correct. I'd missed Frobart's original error in saying, " With the 90 degree squaring...! Regarding the uneven beat the originals were no different, see 10.02 of my video ua-cam.com/video/6zrtxrL-_tY/v-deo.html
To me 'dead centre' at left side piston after first set back. Nevertheless there is another reason.
How can a 3 cyl. engine be stuck on dead center? They (the cranks) are 120 degrees apart! Is the valve timing way out of wack?
'Dead centre' is merely the term used. Please read the introduction notes.
your right cranks are fixed a 120 degrees so the valve timing is a bit out
Today's comment. You can't be stuck dead center unless it is a 1-cylinder loco. If the driver stopped with one cylinder dead center, he has 1 driver 60 degrees ahead and another driver 120 degrees ahead. Steam or vacuum brake problem is first guess at problem. Second guess, not enough steam from the fireman. Remember, all cars are buffered solid, no slack in the train, so the loco starts the entire train, not simply one car at a time. Never had a problem on the 257 Squadron.
I've seen a 2 cylinder steam tractor also get stuck on dead center, mitigated by turning the flywheel by hand a little. It usually points to an issue with the valve timing, but some linkage systems have an inherent error in them that leads to this no matter how you adjust it.
Nice video Alan
What happen in this situation and the whole train is on level ground and won't roll??
See the introduction notes which explain that gravity has nothing to do with it.
What were those dreadful old coaches doing behind it.!I used to watch this loco going through Clapham Junction in the sixties,great memories.
They were teak bodied coaches built by the LNER, and prior to that by the GNR, certainly up to, and through, the 1940's. Although they don't do much for me they are my wife's favourites. I can understand someone who was used to Southern Region green Bulleids and Mark 1s not being impressed. But beauty is in the eye of the beholder Anne!
Is this loco a compound? If so it's easy to understand the problem.
No Nick, it's a simple three cylinder engine.
How does this even happen?
Three cylinders 120 degrees apart.
How on earth does that lock up?
I bet it never happened with a Lord Nelson.
Andrew Muhling it happens quite a lot
Get one or more cylinders at "dead center" with the TWO that are timed together AT "dead center" with the "middle" cylinder unable to start the load alone and what is going to happen? Or what if one or more cylinders are "weak" or "hydro-locked"? What if the whole locomotive is a clusterfuck along with all the others built in a certain country that consistently claims and has claimed to have "superior" EVERYTHING just because its "British" and all that stuff was "superior" in the HISTORY BOOKS but not so much in "real life"?
Two are NOT 'timed together' on a 3-cylinder. They're set at 120 degrees.
Even on a two-cylinder, the cranks are ste at 90 degrees so you can't have 'dead centre'
The ignorance of some of these commenters is breathtaking.
(That comment of mine was aimed at Deeremeyer's snotty comment, not at Andrew who is correct about the number of cylinders.)
It's not possible for a steam railway locomotive to get stuck on "dead center," so what really happened?
See Phil Harris comment and reply for theories.
I thought the cylinders timing would be offset ? so this kind of shit does not happen, as both cylinders are always joined through the driving wheels axles ?
Read my notes for a full explanation. Incidentally, this loco has three cylinders.
Bless the driver… but being a young lad… can you imagine him getting his mobile out and ringing for help… “I can’t get her going … what do I do “ … lol… I’m only kidding … a good learning point
Parsound, you have a misunderstanding of the topic you're trying to address. The valve system, which is designed to time the injection of steam into the power cylinders, is mechanically linked to the driving wheels via rods and cranks. This linkage of the valve apparatus, power piston and driving wheels is synchronised ('synchronized' for American
viewers) such that it will always have at least one crank connection to a driving wheel that is NOT 'dead center'. This is true no matter how many cylinders are incorporated for a given locomotive. What may be misleading you is that train drivers will often create a slack in the drawbar/coupling gear along the whole train by reversing a short distant before starting the train forward. This allows for a train to be started one car at a time, so to speak, instead of a train's complete mass all at once. Additionally, if such a 'dead center' condition did exist, such as a two cylinder steamer running on only one cylinder and the functioning side had the driving wheel on 'dead center' before starting, then that locomotive couldn't move in either reverse or forward. If crew members told you otherwise either they're wrong or they misunderstood your inquiry.
Thank you for taking the trouble to post your comment however, I'm afraid that I disagree. Whilst the piston setting relative to the wheels is indeed immovable the valve settings governing the admission of steam to the cylinders are subject to setting inaccuracies. Whilst the term 'dead centre' when referring to the pistons may not be 100% accurate it is, nevertheless, the term in common use. I refer you to the explanation below from experienced Bulleid driver oly5764. I am familiar with the setting back in times past to lighten the immediate load with loose coupled goods trains but if a Bulleid Pacific needed to do so on level track with only seven coaches it would indeed be in trouble. I would also wonder about the advantage gained when setting back with buckeye couplings! Had it been the weight of the train alone, the engine would have slipped violently, something for which the Bulleids are notorious.
@@Parsound It has happened to me on a loco of this class and it is a result of dead centre as you say, nothing whatsoever to do with brake problems our lack of steam, also happened to me several times on ex Great Western 2 cylinder locos, always seems to happen when there's closed level crossing gates behind the last coach !
Nothing a hefty hammer can't cure.
STOP HS2.
soundslike leaves on the line and the flogger toggle jammed agaist the down riser pipe,
Give it a push! LOL
nooo . you push a kettle, her pride goes away for a while lol. she made it in the end
skp Is going soon
Sadly yes. Probably after Christmas.