P2 discussion (split from train length reduction thread)

I doubt anybody would have paid for a P2 without the success of an A1 first.

Besides - 20 years ago the issues with the P2 weren't as well known and understood as they are now, and computer technology in terms of the sort we've seen in the building of the new P2 was in its infancy.

Building the A1 made sense because it was a missing link and because it was a proven reliable design.

 

I'd have paid for a P2 first and so would have many Gresley faithful.

 

Right - and how far do you think a small band of Gresley supporters were going to get with the reputation of a Gresley P2 as it was in 1992 compared to now with the change in attitudes to new build steam and the knowledge built up from the building of Tornado?

The biggest problem the P2 project faced was getting people outside of the enthusiasts and fanatics to buy into their project. Well they have proved with the A1 first and the then the P2 subsequently that they can appeal to more than just the fanatics and enthusiasts - it's the bread and butter of ordinary people willing to provide regularly that's got them here and will continue to support them.

I'd say the A1 Trust got it absolutely spot on - build the locomotive class that would prove the formula for new build locomotives and then go for the jugular with the P2 to follow on.

The fact of the matter is that they are producing a much better locomotive than the P2 class ever was in service - and let's face it, without their knowledge and experience with Tornado, it's going to be even better for that.

Hell, I'm just about old enough to remember my late grandfather being accosted at a steam railway for daring to support the A1 trust in its early days. "You'll never build that bit". If you coupled the derision and the skepticism with the Gresley P2's reputation and started with that rather than the A1 - well, I think my point is made.

I'm very grateful they're doing a P2 and I'm a founder member - but I'm absolutely convinced they picked the right first loco and second off the back of the first's development.

Sorry to go off topic everyone.

 

There were people who well realised that the steam locomotives working on the mainline were going to be found lacking. They also appreciated that it would take many years for anything to be done about it.

The view held by the majority that what we had was good enough and the best that could be achieved was, and remains, a major stumbling block.

The A1 was in some ways the right choice for the first mainline new build. In others it was not. It remains a Pacific with the limitations of the type. It is steadfastly first generation steam with a disappointing power to weight ratio.

But at least it proved that building a new machine was possible. Was it too little and too late? We will know soon enough.

The P2, the most powerful steam locomotive (certainly on a tractive effort basis) built for the UK, is a more interesting machine than another Pacific offering little or nothing over and above what was already available as preserved. Tractive effort and adhesion. Two of the ways that the battle was won by newer forms of traction.

The 2-8-2 was in use throughout the world. And was such a poor choice and so badly understood?

 

It's all a moot point as we will never know how they would have fared if they had gone for the P2 first. Given the fact that the A1 team could probably sell sand to the Arabs, I've a feeling they would have done OK and never dismiss the Gresley faithful as a "small" group. Reversing something ET did is right up our street.

 

To be fair, the A1 Trust could probably sell sand to the Arabs - now. Whether they could have done in the mid 1990s, when all they had to show was a one page piece of paper with a business plan, is considerably more doubtful. So I'm with @S.A.C. Martin on this one - I think demonstrating the ability to build Tornado was a necessary step on the way to the P2. It is by no means certain that the P2 would have been a success if that had been where they started.

Tom

 

I'll reply in full later but I am sure that's not the case. Off the top of my head, P2 was 43,000 tractive effort, Gresley's Beyer Garratt U1 was in the region of 72,000.

 

broadly In agreement, but I think a lot of the problems eluded to we re P2 problems rather than 2-8-2 problems. I Take it the 6mt is the K1 (or k4) ? Im sure an 8f could get 12+ over shap no problem, because it could still slog away at 15mph without loosing its feet. but that creates rather than solves a problem...

 

As I said in my earlier post, it is all a moot point anyway as without the ability to turn the clock back and start afresh, we'll never know if a P2 would have garnered the same level of support as the A1 did.

 

There's a DeLorean at the Ulster Transport Museum but when I visited last month, the flux capacitor had been removed. Most disappointed.

 

I wondered if you would be awake enough to bite.

I believe we are talking about handling passenger trains here. Yes, I could have written passenger locomotive or even express passenger locomotive but this gets into how, exactly, to view the design. A personal view of this class of machines which were never fully developed. Were they fast enough to run at the speeds expected of the Pacifics while they engaged in express passenger work? I suspect not. The driving wheels were as large as could be accommodated bearing in mind that the class was designed as a solution to a particular rbut the later projected 4-8-2 had the 6' 8" driving wheels used on other express types. So could the P2 be viewed more as a heavy mixed traffic type? As 75mph is the maximum speed permitted today this doesn't matter.

When the Germans tested one of the Norwegian 2-8-4 compounds they found that it was better than a Pacific at maintaining the passenger schedules being used for the trial. True it could not reach the speeds attained by the 4-6-2 but the acceleration available from the modest wheeled compound more than compensated. The compound would probably be more capable in starting away with a load but I have not come across anything to confirm this.

The P2 has a number of characteristics that make it better suited to the modern network than a Pacific. If the BR 9F did not have the flangeless centre driving wheel problem we probably would not be running this thread.

 

The driving wheels on a P2 are the same size as on a Merchant Navy, a class reliably timed on several occasions at over 100mph. So on a suitable road, I can't see that driving wheel diameter (or corresponding piston speed) would have been a restriction on fast running for the P2

Tom

 

The MNs and WCs did have an exceptionally short stroke, 24" compared to the LNER's standard 26", which would help. I always felt that the LMS's Pacifics were held back by their 28" stroke.

 

So basically you were testing people's knowledge. How droll...

I have always been a believer in "say what you mean, not mean what you say". I did wonder if you were going to reply in the manner I envisaged: you haven't let me down yet on predictions yet.

There is a record of 90mph being recorded by 2001 or 2002 I believe off the top of my head. No.2001 was certainly tested at speed on the ECML in her early life and there's actual footage of 2002 doing around 80mph in her original format.

There was nothing wrong with the capacity for speed of the rebuilt A2/2s either and there are (sadly only few) accounts of certain locomotives also touching 90mph and above. But I suspect, not the ton.

Whether built or rebuilt, I don't know if the ton was ever achieved by the P2 class and off the top of my head I don't think there's any evidence to suggest that they did. However 75mph and in and around 80mph seems more than plausible to me - and it's what we're limited to on the main line now so is that a problem?

I don't believe Gresley ever envisaged them as a mixed traffic type and that is probably borne out by the traffic they actually pulled in their original forms. That does not preclude them being excellent power units in their own right and probably capable of pulling all types of traffic with ease (which they did so in the war years before their rebuilding, albeit with more failures noted - more down to both general wartime wear and tear and the inadequate crank axle design I am told. Which is a shame).

The 4-8-2 was never intended to run on the tight curvature or steep gradients of the Aberdeen mainline - only on the east coast main line. So two different classes were envisaged for different traffic needs on different lines - pretty much Gresley through and through. You're effectively comparing apples and oranges. The Mikado was designed to do a specific job, accelerating heavy trains quickly up sharp gradients and removing double heading, the Mountain was designed for acceleration of services and a return to non stop running on the ECML. The former wasn't developed further and the latter was never built. Arguably the original Pacifics and then their descendants were more than adequate for the traffic needs of the railway building up to the end of steam on the ECML.

Seems logical. It's the compromise locomotive engineers have to make. But how interesting that the 6ft 2in Pacific became something of a norm for British Railways, and it took Thompson and Bulleid, then Peppercorn and Riddles to recognise the advantages of this wheel size.

All a bit of a moot point if you compare to Chapelon's Pacifics on the continent and his 4-8-0 though.

As you say (and I agree) tractive effort and adhesion accepted are major advantages - but I suspect the wheelbase will still be a defining factor in the new P2's life. There's no way, for example, the P2 could visit the NYMR (or at least, not long stretches of it) as some of the curves tested Tornado when she visited and the extra length of the P2 wheelbase means it's very unlikely to fit round their curves. In this day and age where Network Rail look to make curves less tight and lines straighter where possible, there's some advantages there.

But the 9F's smaller driving wheels would preclude it from running at 75mph under the current methodology so you're back to square one with fitting a 9F shaped peg into a 6ft 8in Pacific shaped hole!

 

Now the P1 is an interesting beast for me. The two examples of that class were very handsome and they were capable of some prodigious hauling. They were scrapped due to being a small class, but surely they more than the P2s would have been brilliant for the Aberdeen main line - taking up virtually the same wheelbase as their related A1/A3 cousins and yet having much better adhesion?

I have never understood why Gresley didn't just put eight wheel tenders behind them and put them to work on the Aberdeen route. Hell, this was a class which could have been multiplied further and would have been excellent in Scotland. Why wasn't it? Strange decisions all round. Thompson never bothered with them either and Peppercorn's brief reign saw them scrapped. A real shame.

 

This video has the footage of 2002 I mention.

 

Wouldn't the 5' 2" drivers of the P1s have been unsuitable for fast running though? IIRC the P2s had a higher nominal tractive effort so would have had more "grunt".

 

As we haven't yet got a P2 to run on the mainline, does anyone here have an insight into what the A1 Steam Trust think of the proposed reduction in train lengths wrt Tornado's earnings?