Ton up Tornado

Was aimed at the author rather than you Tom. Unless you wrote the book of course.

 

Joke missed in post 221...

 

No doubt in the fullness of time just how hard Tornado was being worked will come out, one suspects that a little faster could have been achieved.
Sure I heard somewhere that the proposed top speed for the P2 would be 85, and looking beyond that at least 75 for the V4. Whats a little puzzling in view of these tests is that although a V4 is by all accounts a very capable and versatile machine and a worthy New build Project, surely another high Speed Cruiser would be a better addition to the stable be that another A1, or perhaps a Super A3 (in effect a 250psi not streamlined A4)...

 

Do you believe either another A3 or another A1 have the marketing potential of a new V4? If so why?

I don't believe either have the raw earning potential at the point of building that a V4 has. Since there are examples of A3 and A1 in preservation now anyway, there's little point.

I should point out the Super A3 has already existed, and she was called Flying Scotsman - fitted with a 250lb A4 boiler and bored out cylinders in the Marchington era. That directly led to the mess the NRM inherited and Ian Riley and his works have put right.

 

There are plenty of potential high speed cruisers among preserved locos, though there may not be the manpower, funds and/or will to make them available for main line running. Whether or not any of them will get the necessary enhanced specifications to qualify for 90 mph running remains to be seen, but doing that for several of them would be far cheaper and easier than building another brand new loco to the 90 mph spec. The A1 Trust's plans to continue with locos that will both fill gaps in preservation and have roles on the main line seem good.

 

I'm not sure what Marketing potential a V4 has, sure its got Heineken route availability, its a very Handsome machine, it was Gresleys last design, and i was delighted when the intention to build one was announced - -but I await with interest what Spin the wonderful Mr Allatt will put on that one
Within a few Years there will be three Mainline registered new builds out on the mainline and maybe the gloss of that will be gone. Looking forward its going to be the trains that earn the Pennies not the Loco.
Clearly whatever niche the A1SLT 'TOC' carves out for itself with Tornado and Prince of Wales they will to some extent alternate as Motive power apart from those two there may be few, or no other locomotives either capable of or permitted to run, in the Paths they hope to obtain, I know there has been talk of a shared 'spare' boiler

The V4's utility will be that it will be able to take trains where the Big boys Cant, but there are several preserved Locos and even one other New build (eventually) available to do this.

Yes I agree there is already an A1 in existence (hardly in preservation) and an A3 but my prediction is that 60163 will perhaps be 'plinthed' in 2036
depending on how feasible it is to resurrect Mallard for her 100'th

Don't need the history lesson , and agree with that souping up a very old and tired Locomotive only served to make it older and more tired very quickly. Building a new one to the correct spec to take a 250psi boiler and potentially smaller, rather than larger cylinders doesn't create a mess (lets hope not for 2007's sake) it creates a locomotive that looks like Flying Scotsman has better RA and is permitted to do 90mph...

 

"Well done Wilson, I was waiting to see who'd spot that first..."??

 

The P2 roadshow suggested that about 80 would be top speed for the P2. I also understand as ever, it's to do with driver diameter.

What about the V3?

 

I suspect the chances of Mallard ever turning a wheel under her own power again are next to, if not actually, zero.

Also, by 2036 how many current main-line locos will have reached the plinth stage?

 

I've been following the discussion about ride quality and hammer blow. IIRC the Gresley and Bulleid Pacifics had the 3 cylinders driving the middle axle, and the Peppercorn and Thompson Pacifics (not forgetting 71000) had the middle cylinder driving the leading axle. Would it make any difference?

 

Indeed it would. With three or more cylinders all driving on the same axle they inherently counterbalance one another
at equal crank angles - simply, reliably and very effectively. The Bullied Pacifics with this rode remarkably well at high speeds,
and apparently the faster the better, they had minimal balancing in the wheels which was only really needed for the
moving weight of the coupling rods. This is why the Argentine engineer Dante Porta's proposal for Tornado was for all
the cylinders to drive on one axle. Hammerblow is virtually non existent.

This is not at all the same with the later LNER Pacifics: which have the leading driving wheels driven by one cylinder
and the second pair by two. The different effects between the piston and crank pin - the piston rod
simply too an fro, the connecting rod both too and fro but also up and down especially at the heavy "big" end -
can only be balanced using counterbalance weights in the wheels by a compromise, optimised but necessarily
imperfect. The two axles do not end up with exactly the the same balancing. And you get hammerblow : which
can be designed out as a vertical force up an down on the rail but this turns it into a longitudinal force
on the axle boxes and the frames - the axle boxes wear turning the locomotive rough and the frames tend to
crack.

At best you are getting higher strains in the axle boxes and the coupling rod bearings. Making them larger,
strengthening the frames between the driving axles and balancing the wheels puts the weight up and the
cost up - both of them directly and indirectly. This is not to say that the ultimate A1s & A2s went badly but
there is good method in a concentrated drive - perhaps best exemplified by what very good engines the Schools
class were.

 

Most people would see a Super A3 as much like and A1. Of course Marchington tried 250psi on Scotsman and bent everything.

 

No spin required. A V4 has been top of the wishlists for some years, after a P2, which of course, is already being built...

??? On what basis do you say that? That seems incredibly long (short?) sighted...

My apologies if you feel talked down to, but if you will ignore the lessons of history...

The RA is less of a problem for Scotsman because she puts bums on seats. Do we need a 90mph A3? Is there even a desire for one?

 

Thanks for this, glad that it has been so well received.

Thinking about 4 cylinder locomotives, particularly those owing their existence to the classic de Glehn layout, what you have is two 2 cylinder engines coupled together. We have much experience with 2 cylindered locomotives, they have their problems but many successful types have been built with broadly satisfactory balancing and so linking a pair of them together within the same chassis became an obvious solution in the quest to achieve more power.

With a three cylinder engine if you split the drive you can probably see the problems. A single cylinder, 19" x 26" in the case of the later LNE Pacifics, driving one axle and two cylinders with cranks set at 120 degrees on the other. The inclusion of an extra set of valve gear between the frames posed an additional problem with balancing when compared with the Gresley design. The LNE paid attention to the balance of the reciprocating parts in the later designs but the fact remained that the new engines were powered on two very dissimilar axles and, as Hirn posts, the frames and bearings are left to absorb this inequality. Not sure what Chapelon did with 242A1 but the outside cylinders had their cranks set at 90 degrees and he did pay attention to frame strengthening. The French also had a reputation for being very good at balancing. And the engine was an experiment.

For LDP divided drive was a "no-no" but 3 cylinder unified drive was the way to achieve high power output designs

 

Fascinating few posts - perhaps explaining why the Thompson Pacifics and the Peppercorn Pacifics were more known for frame cracks at the front end near the cylinder blocks than the Gresley A4 Pacifics which as we know utilized the conjugated valve gear.

Thompson's Pacifics all had equal length connecting rods with divided drive utilized and the cranks set at 120 degrees - perhaps in removing the issues of pin wear and similar in the conjugated layout he (and then Peppercorn) did not foresee issues which could occur as the result of this change.

Fascinating stuff gents, thank you.

 

Driver Diameter need not hinder high speeds, In Australia we have 3 different Class of Steam Locomotive with 5' 9" Wheels Certified for 115km\h (Approx 71.5Mph) and don't forget Norfolk & Westerns J Class in the US 110 Mph on test.

 

Jarvis found a way of fitting three independent sets of Walschaerts valve gear and retaining unified drive on the rebuilt Bulleids.

 

No spin required. A V4 has been top of the wishlists for some years, after a P2, which of course, is already being built...

Yes but whos wishlist... yours / mine /other puffer nutters of an LNER bent... ?
A fantastic job has and continues to be done raising Public awareness of Tornado, a similar effort is underway with Prince of Wales, both are marketable to the general public for different reasons
On what basis do you say that? That seems incredibly long (short?) sighted...
The only basis being the lessons of history; Flying Scotsman has been the Darling of preserved steam on and off since preserved steam began, arguably FS was the beginning. After another twenty years, even in its careful custodianship the chances of FS needing more work will be high, and its popularity lower than it is now... just wait and see.

My apologies if you feel talked down to, but if you will ignore the lessons of history...

I see no evidence of me ignoring the lessons of history... fitting an A4 boiler onto A4 frames with A4 cylinders but not streamlining it is entirely feasible. In any case A4 boilers we're fitted to several A3's in BR Service and functioned perfectly well.... boring the cylinders out to A1(gresley) dimensions caused the problems - but I don't recall suggesting that...

The RA is less of a problem for Scotsman because she puts bums on seats. Absoloutely goddam right, but for other Loco's its a problem.

Do we need a 90mph A3? Is there even a desire for one?

Perhaps not ? The whole slant of my argument is that if you are going to be a TOC that owns its own 100mph approved stock, a 90mph approved loco and an 80-85mph loco that eats hills and TSRs for breakfast and you can therefore propose paths and base itineries on that ability, having another Loco in that category might be more useful than one that isn't.

The logical choice for this would be another A1,A2,P2, or, given the puissant arguments for single axle drive a W1, A4 or a super A3 ( by which I mean a non streamlined A4) or even a Deltic
Apologies if Mr Thompsons experiments aren't really on the Menu.

 

Right: but you have to fund said locomotive and you haven't really explained how you would fund the building of any of those.

Rather unwarranted - not even mentioned in passing by myself. Playing the man rather than the ball there I'm afraid.