The man in charge of resurrecting a giant
David Elliott is tasked with engineering a new-build LNER ‘Mikado’ and improving on the original design. The brains behind the ‘P2’ tells us how it’s being done.
When David Elliott wandered into London’s Great Northern Hotel in April 1991, he had no idea he was about to be publicly ‘pressganged’ into the team seeking to build a Peppercorn ‘Pacific’.
For sure, he’d said he was “interested to come along” to the A1 Steam Locomotive Trust’s second roadshow, at King’s Cross. The commercial manager for aircraft builder Britten-Norman, David had to trek from the Isle of Wight to get there and wanted to be certain his trip wouldn’t be wasted – and he’d sent a CV with a note stating he was “more than happy to look at contracts and commercial activity”, but he wasn’t expecting to be “propelled to the stage with a badge proclaiming ‘contracts advisor’!”
So began a relationship in which David has overseen construction of first ‘A1’ No. 60163 Tornado and now ‘P2’ No. 2007 Prince of Wales – not as a contracts advisor, but engineer. In fact, the London event would become a key moment for the new organisation – for it was the same one that attracted future chairman Mark Allatt (SR511) and finance director, the late Barry Wilson.
Engineering may not have been the focus of David Elliott’s ‘day job’ at this point in his life, but it had absolutely been where he had started. Indeed before crossing to aviation – Westland helicopters, hovercraft and then the makers of the famous ‘Islander’ utility aircraft – David had worked for BR. Joining on an engineering sandwich course sponsored by the London Midland Region in 1969, he had first ended up at Derby, where jobs included solving an unfortunate ‘blowback’ problem on Class 50 urinals. Later came time as senior technical officer at Leeds and traction maintenance engineer at Corkerhill in Glasgow, in among chats on steam with a board member whose name is well known to SR readers – R.H.N. Hardy.
The interest, though, had started much earlier: Mrs Elliott could hardly have thought, when she took a snap of her six-year-old patting Romney 15in gauge No. 8 Hurricane in 1957 (“already besotted with anything that looks like an LNER ‘Pacific’”), that her son would go on to oversee the building of the first East Coast 4-6-2 since 1949.
By the time of the roadshow, David had already been involved with preservation – including helping lay the track back to Smallbrook Junction while living on the Isle of Wight. However, as a full-time railway and then aviation engineer, David confesses that when it came to locomotives, he never quite bought into “the then-prevailing philosophy that you repaired everything. I was trained as
a professional railway engineer… you thought ‘there’s no logic to this. It’s knackered. Throw it away and buy or make a new one.”
Instead, he says, the movement was “recycling components on engines which in any realistic world would be thrown in the scrap bin and replaced.
“Now, OK, if you are dealing with a historical object there is the museum argument that you preserve as much as possible – but it never fitted with me.”
So once he “realised the quality” of David Champion and the set-up team for the ‘A1’ he thought “I really want to get involved with this.”
The switch from offering advice on contracts to a role in the engineering was a result of circumstance. Wellknown preservationist and engineer Ian Storey was part of the group, but “had a full-time business to run and wasn’t in a position to spend much time as a volunteer.”
So it was David who oversaw visits to the National Railway Museum to collect drawings from 1992. The path would lead to him being, first, technical director and subsequently director of engineering; he has been full-time since 2005.
“I fell into the technical director job and have held it ever since, mainly because nobody’s been mad enough to want to take it on from me.”
Preservation or perpetuation?
Neither the ‘A1’ or ‘P2’ are slavish copies of the original designs and, with not much old metal around, you can make an argument that the trust’s approach to steam is less of preservation and more of perpetuation.
However, David argues that “if you look at what happened in main works, we had something analogous to what
the Great Western Society does” with projects like the new ‘Saint’ or ‘County’.
The railways’ engineering plants, he says, “reproduced something looking like a new engine” but “basically chucked a whole collection of standard bits in the air and as they’ve descended, put them into a different order.”
David cites Flying Scotsman as an example, which has “probably only got the back third of its frames and its cab roof original; and maybe four out of six main wheelsets.”
Railways “routinely swapped boilers and tenders about – there really wasn’t a consistent line on most railway companies of an ‘artefact’ which remained that thing throughout.
“It was a line in the asset register, but the fact that the bits of metal attached to it changed all the time is normal and logical. Which is another reason why I was always slightly at odds with the museum approach, where we can’t change anything.”
There could barely be a bigger contrast with the ‘A1’. Rather than a restoration with ‘grandfather rights’ reusing as much as possible, almost everything would be new. This major project would need derogation from rules designed for modern traction, and certification of parts and materials, as much as the bashing of metal.
Creating a locomotive was a process, David muses, that “nobody had done in 40 or 50 years”. Infrastructure was therefore lacking, but the process “fits me like a glove. I was brought up on a farm by a father who was trained as a motor mechanic and subsequently kept Second World War aircraft in the air as a mechanic. So engineering was central to me.”
Framing the future
Yet while undoubtedly the trust’s ‘guiding mind’ when it comes to the ‘P2’ and completion of the ‘A1’ before it, David has never been the only source of engineering input. A major influence in the early days came from Bob Meanley of Tyseley Locomotive Works, where the frames were assembled and much other work was done before the project moved to its own premises in Darlington in the mid-1990s.
One of the big differences between today’s ‘A1’ and the originals, albeit not visually obvious, is that the new engine has ‘one-piece’ frames rather than the originals which were stepped and made from two pieces each side. David says that neither he nor Bob Meanley could discern the reason for the LNER’s designers having specified two-piece frame plates, though he muses that it could have been owing to a post-war shortage of steel; also,
Darlington Works (which built some ‘A1s’ alongside Doncaster) didn’t have a large enough mill to handle 50ft-long frames. So there’s still some uncertainty as to the exact decision-making – but when it comes to the new design, “certainly we’ve had no regret…”
In fact the new ‘A1’ incorporates a good deal that wasn’t on the BR-built versions. However, much of this was nevertheless proven elsewhere before it became a feature of Tornado. So, the air brake system is very much like that on Stanier ‘Pacific’ No. 6233 Duchess of Sutherland; roller bearings (as fitted to original ‘A1s’ but only Nos. 60153-60157) are considered a “no brainer” today.
In David’s view, a more radical departure is the electrical system, complete with onboard generating power. Creation of this was overseen by the trust’s Rob Morland, considered by David as “a genius in that area”. In 12 years of running No. 60163, “we’ve had almost no electrical issues with the loco”, its director of engineering says. Even when there has been something, “thanks to the duplication and redundancy Rob’s built in, we’ve never had a failure yet which is down to electrics.”
Rather than the traditional copperfirebox riveted boiler to the original LNER ‘Diagram 118’ design, in 2005 the trust famously opted for an all-steel, all-welded example from Germany’s Dampflokwerk Meiningen; more recently it has contracted for a further two from the Deutsche Bahn plant; these are to be delivered in the coming months.
However, David argues that the boiler design is “not that radical” – although he concedes that “it was completely different to anything that people had experience of in this country.
“There were one or two examples of welded boilers, almost invariably thought to be poor because the fireboxes didn’t last as long. Nobody really quite grasped the fact that we can have two welded ‘A1’ boilers for the price of one riveted copper firebox boiler.”
Now it might be suggested that Tornado’s boiler was effectively a prototype – and certainly there were wellpublicised stories of cracked stays and foundation ring repairs in its early days. However, David says of such things that “we are slowly ironing them out as we modify as we go” and that “the Germans are very good at supporting us.”
One result is “we’re now getting much bigger lives”; another is that procedures have been put in place for repairs “which we can do in four or five days, if we get a cracked foundation ring corner.
“Tornado’s had all four corners done in the last two years, and OK, if we have to do them every three years, it is a nuisance but it’s thousands rather than tens of thousands of pounds to do it each time and we no longer have to take the boiler out of the frames, which was a big expense.”
Indeed, David reports that the team have now reached a point “where we’re confident it’s routine”.
“More importantly,” he says, “our boiler inspector likes what we’re doing and he’s perfectly happy. So much so that after we repaired the front two corners last Christmas, he’s put another five years’ hydraulic test on the thing.”
A key point for proponents of steelfirebox boilers is that the Tornado versions are “easy to repair because being all-steel, any decent, competent, coded welder can do the repairs for you. We don’t have to get one of these rare men who spend most of their lives repairing stills in the north-east of Scotland where the big copper coded welding supply comes from.”
Plus, David says, “once you’re used to it you can change a stay in an hour. There are no threads to tap; grind off either end, wallop it with a big punch to knock the stay out, cut the next stay, weld it in. Done.”
In addition, the German-style welded, drilled stay “lets you know an awful lot sooner than a conventional stay does.”
If the kind of stay generally used in the UK cracks or breaks, he says, “it’s only detected when you do the washout and the boilersmith goes in and taps all the stays. With us, the moment a stay develops a crack
– and we’ve never had one break right through – water’s getting into the telltale hole and it’s starting to appear. So, in other words, we’re much more conservative in the way that we monitor and change stays than conventional boiler practice is.”
Roughly half the firebox stays are now the flexible versions.
David is clearly very happy dealing with Meiningen, which he describes as “dependable and reliable.” There’s something else about Tornado’s boiler, too: “it generates steam like nothing else we’ve ever seen.”
Although substantially the same engine that first steamed in 2008, more than a decade into its life the ‘A1’ remains, in David’s words, “a continuing development programme”. Much of what has been learnt will help with the ‘P2’ as well.
So, the Kylchap exhausts have been remade in stainless steel rather than the original mild steel which wore away. Stainless has also been selected for new electrical boxes and conduit work to go on the engine at the next overhaul – insulated from other areas of mild steel (“I learnt in the aviation industry that if you bolt stainless steel direct to mild steel, and then apply water, the stainless steel sets about the adjacent mild steel very rapidly.”). The ‘P2’ will have stainless steel conduit from the start.
Giving it ‘the works’
It’s well known that ‘A1’ Trustee Mark Allatt has long wanted to build a ‘P2’. Maybe less known is that David has shared the ambition as well. Formally launched in 2013, the £5m No. 2007 Prince of Wales is expected to steam in late 2022/early 2023 (SR510). “My father had the 1946 Bassett-Lowke model railway handbook that included a picture of a model of Gresley’s 2-8-2, which at the age of seven or thereabouts I fell in love with straightaway.”
David concedes that if someone had launched a public proposal to build one of the big Gresley machines “I’d have probably got involved.”
However, knowing the technical background and the various problems of the original design, David also thinks he “would have strongly courted against doing it the first time round. We had enough risk in simply raising the money and being able to convince anybody we could certificate a new main line loco.”
In contrast, with 49 built that “all worked straight out of the box”, an ‘A1’ was perfect. The Peppercorn machine, he says, is “the final development of the family that started with the Gresley ‘A1’ in 1922 and if by 1948 they hadn’t got the hang of it, they never were going to.”
The “tiny number” of changes made to the ‘A1s’ during their lives shows, he contends, that “they got the design right in the first place.”
Compare that record with the 2-8-2: a tiny class of six, full of differences and with problems including crank axles and a pony truck that “hardly bothered at all”. The last was rebuilt into a Thompson ‘A2/2’, just ten years after the first had been built.
Whereas No. 2001 Cock o’ the North was built with Lentz valve gear, the remainder received a Walschaerts/ Gresley version – and No. 2001 was later brought into line. There were other variations too – including to boilers and draughting, and, visually, the last four engines were built with an ‘A4’-style front end; again, the early locomotives received this later.
Given that history, it’s inevitable that a new one will be different in key respects; David muses that No. 2007 might properly be considered a ‘P2/4’. However, he says, “one thing that you could never level against the
‘P2’ was that it was a pathetic piece of machinery on the road. Virtually anybody you speak to who had any memory or experience of them said ‘yeah, great; never failed to be able to move a train.’” He believes that the notable exception to this was Norman McKillop, author of Enginemen Elite and How I Became an Engine Driver, who, as a union man, reputedly disliked the fact the engines reduced double-heading and were harder work for firemen.
Says David: “You could stick 17 or 18 coaches on the back, the ‘P2’ would set up a 1-in-50 gradient and haul it properly and when you’re an operator that’s quite a nice thing to have.”
Comparing the likely performance of Prince of Wales with that of Tornado, David says that while “we were getting quite well lauded for 28mph for the last three miles up Beattock” on No. 60163’s September 12 York-Edinburgh run,
“if that had been the ‘P2’ I’d be very disappointed if we hadn’t been doing 35 or 38mph; smaller wheels, bigger tractive effort, give it the works. It’s what it’s designed for.”
Raising emotions
David accepts that with changes to the design including the pony truck, welded boiler, valve gear and middle cylinder, “there’s a lot going on.”
He continues: “But the point about this is that Tornado’s a pretty accurate representation of an ‘A1’, but there’s quite a few differences, while the ‘P2’ is going to be, visually, a reasonably accurate representation of a ‘P2’. When I saw that picture at the age of seven in that book, I didn’t know anything about all this grief, I just thought ‘what a fantastic-looking thing that is.’
“And we are, ultimately, funded and driven by the emotion of our supporters. I can’t see how that ‘P2’ can do anything other than raise the emotions – especially when it’s finished, and it appears and it goes.”
He accepts, though, that “I’ve no doubt we’ll have a lot more trouble with teething problems with it than we had with Tornado, although I’m trying to design as many of them out as possible.”
You get an impression that the trust sees its 2-8-2 project as a bit of unfinished business, and David argues that if it hadn’t been for the Second World War and Gresley’s death in 1941 “I think he’d have sorted the ‘P2s’ out. But the problem was, at the time, his drawing office was absolutely stacked out.” Plus, David adds, today’s computer modelling capability wasn’t available.
Thinking in terms of operations, though, David believes that under other circumstances the class could easily have grown to 30 engines “especially in the war, when you’re hauling 23 coaches out of King’s Cross on a regular basis.”
One thing that you could never level against the ‘P2’ was that it was a pathetic piece of machinery
As for the modifications inherent in the new one, this man who is “not a museum purist” says that while “very keen on the aesthetics, as regards what’s going on underneath it, if we can think of something better which achieves the same result or better, is cheaper, and uses modern technology, why not?”
One area where a rethink is unavoidable is the pony truck. It’s long been known that the original was ineffective – and sorting that out was one of the reasons the trust undertook a feasibility study even before formally launching the scheme to build a new Gresley ‘Mikado’. The solution is a welded design based on that of the ‘V2’, which has been put through the railway’s ‘Vampire’ vehicle/track computer modelling and is now undergoing further scrutiny, with consultancy Ricardo going over the calculations.
“There’s a risk they may say ‘well, it’s not going to work’,” says David, “but the Vampire study’s already suggested that it will, and in practical terms on normal track, it’ll ride better than Tornado does.”
The pony truck wasn’t the only source of problems on the original ‘P2s’, which also famously suffered from crank axle failures. These were made from five separate components pressed into each other and over time they worked loose.
The new engine’s crank axle is built to a modified design and a study undertaken with consultant Mott MacDonald “has indicated that we’ve essentially cured the problem.
“It’s not unbreakable, but it will now run for 400,000 miles before any fatigue issue starts to occur,” says David. “The LNER and BR had a policy of changing them at 250,000 miles, which we will
It’s not unbreakable, but it will now run for 400,000 miles before any fatigue issue starts to occur
probably have to do anyway. Also, if we have any doubts, we can ultrasonic test the thing every year.” Today that means every 10,000 to 15,000 miles, “whereas they’d do that [mileage] in a couple of months back in the day. So it’s under no great stress.”
What’s more, crank axle life is not only an issue for ‘P2s’: “I’m just wondering how long this other fleet of LNER three-cylinder engines will go before we have to have new crank axles made,” says David.
Despite the well-known deficiencies of the original pony truck and crank axle designs, David argues that something else is presently the biggest area of uncertainty: the valve gear.
“We think we’ve cracked it, but until we’ve actually done some more actual modelling, including possibly building a couple of fatigue test models of it – various bits of it – we don’t know for certain.”
Prince of Wales is to have Lentz poppet valve gear – as did Cock o’ the North when built – but also learning from work undertaken in the USA, which used poppet valves extensively and undertook development work to
make sure the bits lasted. On the new engine, says David, “we’re basically going to use the strongest, hardest metal we can find.”
He accepts, too, that “the ‘P2’ wore its first set of cams out in 10,000 miles,” but points out “that’s a year’s operation for us.” Having to replace them at such short intervals would nevertheless be an “expensive nuisance”, but David says “if we can get cams to last 40,000 or 50,000 miles, we’re almost at the point where you don’t have to touch them between overhauls.”
Learning from Gresley
So there is much about Prince of Wales that will set it apart from the originals, but the general approach, explains David, is “trying wherever possible to ensure that what we are doing is what somebody else has done somewhere else.
“I am copying the Gresley philosophy. Gresley invented a few things, most of which were significantly unsuccessful – such as his twin-head superheater that he fitted to the ‘N2s’. Basically you had two completely separate heads, and they leaked like a sieve from day one.
“He came up with a two-to-one motion, his own, which worked but had a phenomenal number of levers and cranks in it, which Harry Holcroft promptly simplified and sent back.
“But what Gresley did was look around him and see the best of what everybody else did, and incorporate it on one machine.” Such an outlook is clearly shown when it comes to redesigning the middle cylinder. The trust’s fabricated version is “based on Chapelon principles” as the original Gresley layout had “two fundamental drawbacks.”
Clearance volume is a technical term – being the gap between the piston and cylinder head when the piston is at top dead centre. David argues that this was “excessive” on the original design and, compared with the outside cylinders, also “uneven” – the middle cylinder “was much bigger than the outsides, and that was because the valve chests where on either side of the middle cylinder as opposed to next to one another.”
So for No. 2007 the two valve chests have been brought together, with a rocking shaft drive. Rocking shafts, David points out, are “everywhere on steam locos.”
Another aspect has also been done away with. Explains David: “The LNER machines had several places where exhaust passages are directly in contact with incoming steam, separated only by an inch of cast iron. It’s believed the ‘P2s’ actually superheated their exhaust steam as a result, with heat transferred from the incoming steam straight to the exhaust without bothering to go through the engine.”
David says he can’t fathom why Gresley allowed it in the first place (though he says “I suspect he gave it to somebody who was an expert at designing cylinders, but had very little understanding of thermodynamics”).
“This,” contends David, “also accounts for why the original ‘P2’ tore the fire apart. You’ve put so much more energy into the exhaust that the blast is a lot fiercer than it should be.”
Such things should be no more. Explains David: “I’ve completely separated inlet and exhaust, leaving an air gap at least in between, and wherever possible we’ll put ceramic insulation between them.
By mimicking the outside cylinder design on the inside, we should have virtually identical clearance volumes.”
That will eliminate another unwanted characteristic: “You won’t get the uneven exhaust beat for which the original ‘P2’ was famous.”
Despite all these modifications, though, many aspects of the new engine are familiar to Tornado’s builders. A conscious decision has been taken to carry things over and standardise in various areas: tender, boiler and the electrical system are all very much based on those of the ‘A1’.
Completion of the first ‘P2’ since 1936 is now expected in a little over two years, before an expected lengthy shakedown period (SR510).
“I have no doubt that when we do finally put this together, some ‘gotcha’ will get us,” says David. “But that’s why we’re allowing a year to put the thing into traffic rather than three or four months as with Tornado, as it gives us time to modify things and make new bits if we have to.”
Creation of a new ‘P2’ will undoubtedly be a huge achievement for the A1 Trust, and also for David Elliott. Given all the work to bring the ‘Mikado’ up to date and resolve the design’s historic problems, is the new machine perhaps actually a GresleyElliott ‘P2’ rather than a straight Gresley engine? “Well, it is a bit,” David accepts, but adds, “I am doing my best to be a continuation of Nigel Gresley, within my limited sphere. I will never have the brilliance of industrial design and intellect that Gresley had, but I do have a good understanding of what he was trying to do.”
Today’s amazing place is a long way from being propelled to a stage in 1991, and David is well aware that his CV is an unusual one: “For the last 20 years I have been paid to carry out my hobby and not many people get that opportunity. “Plus,” he says of the team behind the A1 Trust, “this lot are the best crowd I’ve ever worked for, or with, in my life!”
●● This article is part of a series marking the 30th anniversary of the A1 Trust.