Tornado

Steve it’s not that I disagree with you entirely, I understand your point, these machines flex a lot, which is valid, but flex does not preclude the need for correct tolerance and machining discipline.

Is there any actual evidence around that running boards speculation?

As for provenance of parts/materials, the modern materials are far ahead of what was available in the 60s, and light years from the 30s, but by suggesting that the A1 trust has assembled something of lesser quality than that produced by BR is to suggest their QA and QC is not as stringent as BR’s.

Something I highly doubt given the regulatory oversight from DB and NR is very thorough.

Unless of course you are suggesting A1 SLT suppliers are falsifying material spec sheets? Are you?

Be careful here. There is very little/zero evidence to suggest anything of the sort and in fact all evidence points to the utmost professionalism on the part of all concerned authorities including A1SLT. A point Iv made here before.

Anyway. Are some poeopke on here suggesting that we weren’t going to learn things from building a brand new steam locomotive? Are those of you being critical so naieve as to think that nothing would ever go wrong with a steam locomotive, new or not? Why do the A1 group get such high scrutiny?

I think im starting to understand why other operators just keep it all behind closed doors.

 

Couple of things that strike me as different about Tornado as a new build:
The precision with which parts have been machined, and the quality of its materials are extremely good, and this is one of the reasons why the machine has run pretty faultlessly, straight from the box, for 10 years. The rates at which certain improved components wear out/ cause wear on adjacent materials is maybe an unknown quantity.
Also in terms of re-design. The tornado frames are overall slightly thicker ( metric creep) than the original constructs and therefore more rigid overall - apart from the area around the cylinders where a single thickness frame has been substituted for a double thickness sandwich. The flexing / movement in that area which 242a1 has eluded to is surely more likely to occur with the former arrangement rather than the latter.

 

There is much guesswork in the above comments. The A1 Trust, DBC and NR are those with the engineering information and will make rational decisions. I am not going to add anything other than that a very similar discussion has been going on in vintage motorcycle racing for decades without resolution. Here on NP I look forward with pleasurable anticipation to pages of speculation ranging from utter b*ll*cks to informed engineering analysis.

 

Very well said Kylchap! I think this failure with Tornado (which some choose to call a catastrophic) has turned out almost like storm in a teacup.

Sadly it seems to be a human bad habit to let some darker episodes in life completeley overshadow all the woderful joy you actually have experienced....

Knut

 

So lets step back for a minute, and put all preconceptions out of our heads. Any tribalism, anything personal - lets just throw it out for the window for the time being and think about this and the history behind the Peppercorn A1 design.

• Divided drive on three cylinder locomotives.

26 Thompson Pacifics and 65 Peppercorn Pacifics have been built with this setup. Within the sub classes A1, A2, A2/1, A2/2, A2/3 and A1/1, there are two key differences. The centre connecting rod on classes A1, A2 and A1/1 are different sizes to the outside connecting rods. All others had equal length connecting rods. This affects balancing and overall setup. A further difference is frame arrangement. On the Peppercorn machines, the frames and their stays at the front end are set up differently to the Thompson machines due to the centre cylinder being more steeply inclined and also being brought further back due to the shorter length connecting rod.

These differences are not subtle, you can see the different setup in the outlines of the locomotives. For comparison:



When you look at the position of the cylinders on the A2/2, you can see that the frame extensions fitted to the original P2s to convert them to Pacifics start directly behind that of the outside cylinders. In practice, the A2/2s front end flexed more and frame cracking was not uncommon in their later life under BR.

On the later Thompson Pacifics A2/1 and A2/2, this was revised but the general setup of the equal length connecting rods remained the same. Frame cracking not common.

On the last Thompson Pacific, A1/1, Great Northern, the connecting rod for the centre cylinder was a slightly different length despite having broadly the same setup. Frame cracking as far as I can see from my notes, not an issue. Great Northern's frames were not based on the 6ft 2in machines, it in fact had a set of frames based on the Gresley A4 Pacific setup, albeit the cartazzi arrangement was slightly different and the front end modified to take the revised Thompson front end arrangement. This set of frames was unique and lasted to 1960 when Great Northern was withdrawn with a worn middle cylinder.

The 26 Thompson Pacifics were no slouches, though their annual mileages were lower overall than the other classes. A1/1 Great Northern was the highest mileage Thompson of the lot. The availability of the original Thompson Pacifics during the war was good to excellent - so in practice there is clear evidence that the divided drive layout was not a problem in everyday use, particularly when fresh out of shops. There is anecdotal evidence for their rough riding when run down. Equally there are several accounts of 90mph+ running with the 6ft 2in Thompson classes.

The point I am making, is that these were the Pacifics considered to be the weak links by a number of people in railway history - followed by the Peppercorn A1s which arguably came out on top as Britain's best Pacific class. High mileage, lower maintenance costs, better revenue per mile figures.

We're not talking about a locomotive design that was plucked out of thin air and put into service: the LNER first started using this three cylinder, divided drive setup in 1943 with A2/2 Thane of Fife - tested it for an entire year on its own - then converted the rest of the P2s - and continued building variations of this setup until the end of 1950 at Doncaster works. British Railways Eastern region then ran all of these locomotives until 1958 when the first withdrawals started to occur due to the modernisation plan kicking in more markedly.

Put simply: this version of divided drive itself is not an issue. It worked. It worked in daily service from 1943 until 1965 when St Mungo was withdrawn and has worked since with A2 Blue Peter in preservation. So any arguments against the setup in terms of the practicalities of the setup are spurious. There may be setups that have advantages over this setup, certainly. The body of evidence shows that the arrangement works fine in practice and has done for several decades both in work and preservation.

• Frame cracking

This can be put aside - I cannot see anywhere in the news that Tornado has suffered this. Mention was made of the "running boards cracking" and again I cannot see where this has been mentioned. If someone would care to point me in the direction for the source of this I'd appreciate it.

However blaming divided drive on frame cracking is a misnomer. The worst offenders of frame cracking in LNER days were the Gresley A1s and A3s, requiring up to 3/4 length replacements of their frames in their working lives. The actual design for the frame plates and their stay setups changed a number of times, culminating in the revised arrangement that the A4 Pacifics had - which did not suffer from frame cracking so markedly. One could cogently make the argument that driving all onto one axle as these locomotives had increases the stresses in a specific area rather than spreading the overall load. A fascinating pros and cons discussion given other designs in preservation. Within LNER practice, not a big deal.

Tornado's frames are however slightly different to the originals - metric from imperial conversions has resulted in slightly thicker frames. I do not feel - but more qualified engineers than I may choose to comment - on whether there is any inherent advantage or disadvantage in this over the originals.

• Assembly of parts from different locations

Since big four and BR days, the railway has become stricter on paperwork and evidence led investigation. Tornado has been built over a long period of time and parts have come from all over the world, but each item made for Tornado is traceable back to its original source, has receipts, audits and NDT testing done prior to final assembly in many respects. I would therefore argue Tornado is likely to be the first preservation era locomotive where the full provenance of every component is genuinely known and traceable back to its source.

I should also point out that tyres in preservation generally come from south Africa, components saved by one group routinely do the rounds and get donated to others, we order in sheets of various precious metals from abroad...point is that railway preservation is full of sourcing parts from all over, it's how it has survived. If we only took parts from this country we'd find ourselves up the creek.

* * *

At this point I will get off my soapbox. The bottom line is that it is unfair and inaccurate to state divided drive is a problem in itself. All railway engineering is a compromise to some degree. The evidence of everyday service of the originals and those before them show a pattern of reliability and several decades of work without major alteration to the basic setup.

Where Tornado is concerned, she is not fatally flawed. That line of thinking is not in my view accurate or fair. Undoubtedly lessons are being learned all the time from her. She's not just a prototype for building others - she is providing a blueprint for others to follow. That includes observing any issues or mistakes and taking it all on board, good and bad. For that, I am grateful and we all should be.

 

A basic question:- If a steam locomotive of any type has a cylinder which is not concentric along its entire length, valve rings with insufficient gaps and inadequate lubrication, is the probability of the piston seizing in the bore greater or less if the locomotive has divided or unified drive?

 

Neither. The two are not correlated.

 

No disagreement with your basic point, but on this specific one: materials properties are far better understood, and uniform, now, than they ever were. Ditto for quality; we now have NDT, measuring, etc that 50's engineers could only dream of.

Now, whether the sum results are any better, I don't know. But I've just been reading 'East Coast Pacifics at Work', and I was slightly astonished to see the discussions of all the in-service failures. Measured against that, Tornado's not done too badly so far.

Noel

 

That's very cute, like. How does one bore a cylinder that isn't concentric along its entire length... something about the action of the valve piston in the liner must be at play here, the rings maybe the tool is something odd happening with the valve rod ?

 

As I understand it from the convention, the lack of concentricity is between the valve spindle centre and the bores - ie one or both valve chest bores were slightly off-centre. The Trust's engineers have designed a gauge to measure this, and to ensure it couldn't happen again.

 

Where have I said or even implied that the A1 group have done any of those things? All I have said is that steam locomotives were not built to close tolerances. Those who designed and operated the last steam locomotives had the benefit of 150 years of experience in doing so. With few exceptions it is now fifty years since people were so involved and anyone with such experience is going to be at least 70 years old, and more realistically much older. A very experienced design engineer at the Hunslet Engine Co. once said to me that you can't apply normal industrial standards to locomotives; they need to be tractionised (the word he used.) I don't think he was wrong. New build in the 21st century is effectively having to go through a new learning curve.

 

Ah sorry Steve, not all of that was directed at you, only the first paragraph. The rest was more general about what others have said.

Agreed to a point. But we know where we differ, that’s ok. They are highly dynamic machines and require shaking down and real world experience to get the best out of them. We aren’t really far apart.

Indeed, that was my point too. There were always going to be lessons learnt here, which is to be celebrated. I think the A1SLT are doing a great job of that process and are to be applauded for being so public and transparent. This engineer wouldn’t be if it were his call!

 

This discusion reminds me of a tale I read in someones autobiography. There was to be a VIP visit to a works where the VIP was to alight at a tempoary platform in the works. The route to the tempoary platform had a tight curve so a dress rehersal was arranged. The loco went round the curve no problem. However the loco inspector thought thr axle boxes on the chosen loco were a bit loose and had them fixed. At the same time and without conferring the PW inpector was woried about some sleepers and had them replaced and rhe line fettled. On the day of the visit the loco came straight off the track into the dirt.Sometimes that loose tollerance is a good thing

 

Reminds me of dolgoch on the pre preservation talyllyn... Loose tolerances galore

 

While the funding for Tornado is very impressive and model that many could do with emulating, it does strike me on how much money this engine appears to generate, including when it is in traffic and covenanters and fundraising continues unabated. You would think that it would have reserves, all parts paid for, rather than need to launch another appeal...

 

Even if they have the money they need in the kitty, doesn’t hurt to have an appeal to replenish it. In preservation the fund raising never stops.

 

Very true and nothing wrong with that, but by comparison with others, the PR and fundraising machine that Tornado has generated has been much bigger and much more successful. Especially when most locomotive groups would set membership at about £15 a year, whereas Tornado Covenanters, pay £10 a month for an engine that's built... This on top of all the monies and funds made from visits to heritage railways where the fees for Tornado are higher, and the money from tours.

Just pointing out that there seems to be a lot of large revenue streams that bring in funds and let others ponder on that.

 

Not entirely sure what point you area making but even in good times the accounts show that Tornado absorbs rather than generates cash, which the A1 Trust are clearly aware of. The model seems to be to get the supporters to fund the shortfall, in the absence of other commercial revenue streams to supplement the direct revenue.

 

May I point out that you are perfectly at liberty to examine the trust's accounts submitted to companies house, as per all of the locomotive groups, if you suspect foul play.

That's two strange inferences in a few pages. I think other locomotive groups may have a point regarding putting things out for scrutiny in the public domain: nobody can criticise or analyse if nobody knows...

The level of conspiracy theory in railway preservation does get silly a lot of the time. Sometimes a firing shovel is just a firing shovel.