Discussion in 'Steam Traction' started by aron33, Aug 15, 2017.
Split the difference and turn it out in red lead ....
Simon has established how bad the P2s were. The crank axles were part of that, but do we know what else was wrong with them to cause their extremely poor availability? Pony truck performance was a weakness, but did it actually affect availability? Claims of track spreading seem to be of dubious validity.
If the new one runs over the modern network with few or no problems, as expected, that won't really tell us much about the originals, except that they were a near miss.
In generation 0 you need to add 1827 Royal George by Hackworth https://en.wikipedia.org/wiki/Timothy_Hackworth Think this is classed as the first 060 in the world.
Yes, but it doesn’t survive. I was only listing survivors, to show that actually there is a very good spread.
Yeah, I had a similar thought, later. For instance, the crank axle failures: they didn't appear right away (I'm too lazy to look and see exactly how long it took for the first one), but IIRC after some period of service (which makes sense if they were in part a fatigue failure), but I doubt PoW is going to be running the kind of schedule that will rack up hours anything like as quickly as the originals. And the theory that side loadings at the rim (caused by the long fixed wheelbase, on curves) were part of the problem; track changes to reduce curves since the 30's may take that out. So although we'll get some data out of PoW, it probably won't be very definitive.
Of course, if the PoW crew were so motivated, they could do some actual experiments which could provide some useful data; e.g. instrument PoW's crank axle with modern strain gauges, and then run it around as sharp a curve as existed on its route back in the 30's (I'm sure they can find one somewhere), and see what it actually experiences. (The real world is always superior to any mathematical model.) They could then do the same with Tornado, to see what a Pacific sees on the same curve. Etc, etc.
One for the Thompson thread I suspect, but Thompson had far more to do with the various rebuilding of 4-6-0s and 4-6-2s than he did the P2s when he was an assistant to Gresley. Even the W1 he had more of a hand in, being involved during its work in its original form (albeit more limited than with Bulleid) and notably in charge of its rebuilding at Darlington when head of that works.
The P2 as designed did have a few issues. The LNER following on from the GNR used swing links for the control of leading trucks and these appear to have worked well enough on the GN mainline. Many of the shorter wheelbase locomotives survived unchanged until the end, the Pacifics originally had swing link controlled bogies but the design was changed starting with tests in 1931. The length of these engines was seen as posing problems for the original fitment which was largely identical to that fitted to the C1 Atlantics. The P2s were built between 1934 and 1936 and the Pacifics received their conversions to sprung centring bogies largely in 1933 and 34 and proposed P2 designs certainly date from the March of 1932. Possibly a little too early for anyone to consider that the length of the locomotives might present some problems when it came to the control of the front of these machines.
The official minimum mileage to be attained between general repairs was 70,000 miles though figures well in excess of this were recorded prior to WW2 - 2006 achieved 118,930 miles before entering Doncaster Works in the May of 1939.
The Company did look at the crank axle and it was calculated to be less stressed that that fitted to the A3 however the Pacific would slip and so protect itself so to speak. The 2-8-2 didn't and wouldn't. The failure of the leading truck to guide and support the engine when worn may well be another consideration. Staff at Doncaster knew that the design needed changing but this never came about but at least it was identified many years ago and is not a new revelation.
The minimum radius of curve that the engines were allowed to negotiate was 7 chains/154 yards (140.82 metres) and you could set the wheelbase out on a drawing, carry out the necessary calculations and identify what was being required in terms of the lateral play of the axles in order to achieve this. You could then compare this with the clearances allowed in the originals and so continue. Fortunately we have computers and programs, (or programmes) that can save us a great deal of work. And as you know these have been used.
I agree with you but felt it necessary to point out that watertube boilers functioned very well in what might be termed less than ideal circumstances and we know that some ships suffered damage when the main batteries were fired, shattered plumbing, lockers torn away from bulkheads, fractures in beams and so on but the engine rooms were able continue to function. Warships have been damaged to the point of sinking but the engines have worked to the very end.
One of the last trips I did deep-sea was on a steam tanker (I never really liked 'hot fog windmills'! - give me a motor ship anyday) which had been retro-fitted with a Controllable-pitch propeller, which was fine from us Engineers as we not longer had to stop the main turbine, to go astern, but it did create demands on the water tube boilers that were never intended, as the vessel could go from full ahead to full astern in seconds ... kept life interesting for the boiler room crew.
Never heard of a Turbine driving a CPP before.
I did hear a tale though of Babcock Engineers rapidly exiting a boiler room when they discovered a boiler intended for power stations in a tanker, reinforced with steel straps!
Old hat in the RN - the Type 42 destroyers had them running off gas turbines and they were designed in the 60s (actually, a lot of the tech in them was 50s...). Overall it's kinder on the turbines with the thrashing we used to give them.
I'll be honest I'm really surprised that anyone still talks about building more new builds. With everything that has gone on in the last couple of years and the loss of money to heritage railways, loco groups and all other groups, talk of even more is surprising. So far not a single group has managed to build a loco (standard gauge) in under 10 years. Even groups with donor parts seem to take 15 years plus, and with 95% of the money coming from people who generally remember steam locos in BR service, another 10-15 years from now how many of them will be around to see things?
Shouldn't heritage railways really start to look at getting costs of things down as much as possible before creating more things to look after? More undercover storage is surely the best thing right now?
My dad has just turned 70 and was one of the younger people involved with the SVR when it opened, and realistically a new build that starts right now would take a minimum of 20 years to complete going on past performances of EVERY new build that has come before.
And that doesn't mention operational problems caused by environmental issues and the planned removal of fossil fuels to alleviate them. Will we still be able to use steam engines in twenty years' time?
All of which makes sense in a vacuum, but assumes control over other people's wallets. The money that I give to the Clan Project for example, is not available to be given to something else just because that's what others want me to spend it on...
Now, that doesn't also stop me being a member and shareholder of the SVR (and contributor to the latest shed roof appeal), and member of the Lynton and Barnstaple, Great Central, Talyllyn, Didcot, Chinnor and Princes Risborough, Northampton and Lamport, and 82045 as well, but I'm giving money to the Clan because heavy engineering from scratch appeals to me (and I love Clans). And here's a thing, even if it's never finished, the journey is worth it, because lots of discoveries, work arounds, and skills are being discovered or rediscovered.
You'd have to be able to prove two things:
1) That new build projects are detrimental to the wider movement
2) that if you closed the projects (or somehow achieved a moratorium on new ones) tomorrow, the people and money will somehow be available to the other needs. It won't be, because some supporters of new build groups are, get this, more interested in the engineering than they are in railways...
Stopping 'Dave and his mates' from wanting to build an A5 doesn't necessarily build the GCR a carriage shed.
This is part of the overall problem when talking about LNER locomotive history. The LNER itself did not place mileages between general overhauls as the primary factor in locomotive running (though it was recorded on the engine record cards). They looked at the average mileages per year as their main concern. That's why the Use of Engine Power document from the National Archives is so important: it clarifies substantially what mileages should have been aimed for each year. The P2s were meant to be achieving 50-70,000 miles a year, and 70,000 miles between classified overhauls, which is yet another subtle distinction we need to make when considering the value or otherwise of a locomotive to the company.
That 118,930 miles that you quote for P2 no.2006 is over a period of three years since its build date in 1936, so gives an average annual mileage of around 39,643 miles per year, making her the best of the P2s pre-war for average mileages. The average annual mileage for the entire class fell significantly during WW2, which was a principle factor in their rebuilding.
This is probably better served for discussion in the P2 or Thompson thread and I welcome such a discussion there if necessary.
At the last GCR 567 Supporters meeting (back in 2019) it was said that options were being held open to planning for using "alternative fuels" for it in the future if it comes to that eventuallity.
There is another meeting this coming Saturday so it will be interesting to see if this gets mentioned again, though the way forward with the entire project is more likely to be a higher priority having lost more or less 18 months of work on it due to Covid and the Ruddington shambles.....
Perhaps the question is more properly "Will we still be able to use coal or oil fired steam engines in twenty years' time?". If the answer is 'no', then we're in real danger of being left with a lot of inconveniently large and expensive ornaments, of no remaining practical use, beyond that of static exhibits.
Other looming problems surround the collective ability of our movement to restore and maintain kit, from drainage gullies to locomotives.
It would be be more conducive to open discussion of problems and possible solutions if there weren't a significant and vociferous number who perceive no problem, let alone urgency and who'd far rather any and all attempts to broach the subject were shut down. That way lies disaster for our movement.
Well, clearly their model was incomplete (or inaccurate), since the axles did break! Now, it's true that:
and maybe that's the whole answer, but I suspect that the true answer (like most engineering failures) has a number of related, interacting factors (including detailed design issues like sharp corners that produce stress concentrations were cracks can start, which have now been rectified) - but without actual measured data from a test in actual service, I wouldn't be 100.0000% sure they'd got them all.
Required annual mileages are a tricky area, as there are so many factors to be taken into account, such as the type of work and where it was done. Express passenger engines could attain high mileages, although availability would be low as mileage-based exams became more frequent; while a heavy goods engine, plodding along at low speeds with many stops in sidings, would achieve far fewer miles run despite, probably, more days in steam. To move to a subject I know, Stanier's Big Lizzies south of the border were achieving around 80,000 miles per year, while those north of it, generally running shorter distances, were quite a bit less. 6256 and 6257 were intended to top 100,000 miles per annum but rarely, if ever did so: they were working the same diagrams as the other thirty-six engines so the chance to do it simply wasn't there.
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