New Build P2

You are forgetting something chaps. The different across the frames dimensions of the P2 and the Duke.

 

Did the 'Duke' share the same frame/wheel-web arrangement as the Brits then?

Foxy

 

Same wheels etc, Pretty much in terms of frame spacing (longer extension frames), but the arrangement of the frame stretchers smoke box saddle etc is different as theres another 'engine' to accomodate.
As mentioned earlier the Gresley designs dont have the frames positioned centrally on the horn guides, the wide firebox standards did.

 

Would make sense and even though having an express passenger loco with nigh on 50,000lbs of TE would be rather cool, something around the 43,000 of the originals should be ample in this day and age. I so hope this gets built.

 

What I meant was did the 'Duke' have the narrower frame spacing of the Brits, which had the web of the wheel on the reverse side to allow the largest possible cylinders to be used within the loading gauge. If they shared the same wheel pattern that answers the question... thanks.

Foxy

 

Reducing the cylinder diameter to reduce the steam consumption? Ah, no. Just how do you expect that to work? Modify the cylinder design to reduce the specific steam consumption. No reason not to if it is necessary to reduce the cylinder diameter because of loading gauge problems. The BP could then be tweaked to balance out the TE equation with due regard for maintaining an adequate factor of adhesion. Gresley did a significant amount of work on Caprotti gear prior to WW2 so the justification for this modification does not go back to Peppercorn/Harrison but to the activities of the great man himself. The Lentz gear had a number of problems, one of the main ones being high clearance volumes (anything up to 16.1% on 2001, never more than 7.83% on 2002) but no one mentions leakage which is one of the reasons Chapelon reverted to piston valves. The BC gear has been equaled by the best PV applications and there is improvement to come in this area without undue complication - the mechanical failures and complexity of the BC gear should be a cause for concern if long term reliability is viewed as being of great importance.

In spite of the facination with 2001, 2002 or rather 2006 would probably be a better choice for a new build - you could even apply a modification to the valve gear to allow the lead to be varied for any cut-off, training people to use such a facility would be an interesting trick.

The mainframe spacing on the P2 was 3' 11.25", not the same as the Pacifics, which should give room for some controlled lateral play in the chassis design.

 

With the generous preservation numbers of A4s, I can see the desire to create the unique external form of 2001, as originally built. It was modified allegedly to improve smoke dispersal but one wonders whether Gresley had some desire to achieve a consistent house style with the A4s. The casing / deflectors on the Bullied pacifics were fiddled with to improve such matters with little overall change in the recognisable design and I am sure that the same could have been done with the original 2001 arrangement.

In relation to the valve gear, there is no point in reproducing, for historical reasons, arrangements that did not work too well. I like the theory behind using BC, but, as the 71000 folks know, a new BC box is a huge expense. Everyone has to acknowledge that there will be thousands of variations from the original, many more than in Tornado because even the original A1 design had the benefit of 14 years' experience and progress since the P2s. By the time one has allowed for design in SI units, modern materials, modern manufacturing methods, modern lubricants and all the inescapable H&S requirements, good cosmetic resemblance is probably the best objective. As for stresses, the 5AT people envisage 180km/hr from an 800mm stroke. By comparison, a P2 with a stroke of around 686mm should be quite long-legged!

Finally, I was following the renewed debate about the merits of Gresley and Thompson with some sadness. Gresley flourished in the more spacious days of the 1920s and 1930s whereas Thompson was thrown into responsibility in the middle of a war with railways under Government control and economy of cost, time and labour the criteria for gaining Government approval of new construction. Thompson's approach seemed not far apart from that of Riddles who produced crudely effective locomotives in wartime but rather more refined, though still straightforward, ones for BR. Of course, he was not working under such urgency, and his staff were not trying to design locomotives between trips to the air raid shelter.

 

You will have to make do with this one for the moment.

A Small Video of A 71/4'' gauge (1.5'' scale) P2 locomotive. - YouTube

 

Would it be possible to (re)christen the new P2 with the most beautiful , magnificent,poetic wonderful, dreamfully , glorious name ever carried by a locomotive , in all the world ie "Wolf of Badenoch" ???:first:
regards
Noel

 

Yes another locomotive named after a serial rapist is really what the world needs.

Tim

 

With the sharper blast of the poppet valves the original front end of 2001 provided sufficient lift to the exhaust but the softer blast of the piston valves on 2002 required extra deflectors. By the time the final four P2s were built the wedge nose of the A4 had demonstrated its efficacy in lifting the exhaust so when the other two went for overhaul and in 2001's case piston valves fitted, the wedge nose was fitted too. I have read nothing to suggest the fitting of the wedge nose was anything other than to improve smoke deflection.
As I understand it the new P2 valve gear will not be reproducing "arrangements that did not work too well" but replacing the Lentz as fitted to 2001 with British Caprotti gear.

 

Wouldn't that be Lalla Rookh?

 

Luckie Mucklebackit.

 

I don't care about the historical background! I consider only the beauty of words!other superb name "Ottery saint Mary" (WC 34045):angel:
regards
noel

 

How about "Tam the Gun" in honour of the late Staff Sergeant Thomas McKay MBE, the District Gunner who fired the One O'Clock Gun at Edinburgh Castle? I know a Class 91 has already carried it, but it is probably a 'safe' option if you don't like naming you locos after Medieval Scottish rapists...

 

I agree steamdream, don't worry about what those others say! No soul! I think some of those LNER names as given to the various pacifics were the best & most inspired in the country. Lets keep the tradition going by naming from the Walter Scott novels, the best ever names!

 

Sadly I can only think of one or two names for a new P2. Karen Gillan or Amy Pond.

 

If you're going to discuss names then what's wrong with the original "Cock O' The North" ? After all the loco will be built in the North of England where manufacturing still has a base and although it emphasises the North South divide why shouldn't the North take pride in success. The P2 will recreate an earlier era so why shoudn't it use the original name as part of the recreation ?

 

Or angel of the north ?

Theres always "Scottish Tornado".. After the weather and reference to its 21st century parentage
Or Scotland's most famous 21st century character Gordon brown..
That would lend itself to "Lying Scotsman" or "Banker of the North"