P2 Locomotive Company and related matters

Harking back to the question about CAD design, Tornado was not CAD assisted at the outset but many of the common component drawings were subsequently created in CAD and much of No. 2007 will go straight from CAD to metal. Talking of which a whole bunch of new components has been delivered to Darlington to accelerate the wheeling process:

https://www.p2steam.com/2017/02/05/further-progress-more-components/



Foxy

 

Someone has been reading their speeds and feeds tables! Good work!

Those trunnion guides are cnc art!

 

Completely agree, those machined parts could be classed as engineered "p@rn".

The level of detail, and finish are to be highly admired,

Keep up the great work!!

 

Even the small step on the footplate looks elegant!


Foxy

 

Ooooh Lovely
That Gresley bloke knew a thing or too about elegant running plates.
(Unfortunately the incursion of the valve gear spoils the P2/1 just a little)

 

It's more likely that such detail was down to his Chief Draughtsman

 

The only part of the P2 that looks a bit brutal is the double depth front buffer plank, it is a pity that a double drop couldn't have been incorporated into the running plate to avoid such a blunt end.....

Foxy

 

The Option to try one with Lenz gear was made fairly late on and yes it would have been the Drawings dept s task to make it fit .Indeed, the original running board, (see Earl Marischal)had a characteristic dip down onto the top of the cylinders ( like an A1, P1 V2,4, K1,2,3,4 etc ..).
Whether this was actually a Gresley thing or a Bert Spencer thing will we ever know, Ted Windle seems to have left it alone until Thompson came along.
I agree the drop at the front is pretty abrupt... to put a curve in it would need footsteps adding for safer crew working (Like on a castle for instance)... and or making the loco longer !

 

Nice to see one of the bits I sponsored in that photo...

 

It's interesting because everything I have read and observed about the three LNER CMEs was that they were very hands on when discussing such details.

They may not have drawn it themselves - that was down to the draughtsmen - but Gresley and Thompson both did get involved in the aesthetic and practical details: very much so.

Gresley's work with the corridor tender and Thompson's with the B12/3 valve gear spring immediately to mind. Both also were very specific about the requirements for things such as the cabs.

Of course a CME doesn't get involved down to the smallest details, but I think the LNER were very lucky in terms of their CMEs that they did have that kind of mindset of wanting to be involved.

 

Think its great how even for a steam locomotive where so much form is down to function just a few consistent features create a distinct family identity.

 

I don't know. Despite severe LMS leanings, I would admit that this was amongst the most handsome locomotives ever to run in this country. It's a beautifully balanced machine just as built.

 

....and yet even No. 2002 has a deep buffer plank. Why, I wonder?

Foxy

 

A good question. As far as I can see from a quick look through published pictures, all the LNER pacifics, even including the A2/2s rebuilt from the P2s, had a deeper step down to a normal-height buffer beam. Did that higher platform at the front of the P2s hide some gubbins (e.g. conjugation lever on the piston-valve ones) that wouldn't fit if the platform were at the normal height?

Andy: are you reading this? Do you know?

 

The combination lever on No. 2002 was behind the final drop to the buffer plank so that can't be the reason and even on No. 2001 the strange cowl/faring ahead of the cylinders seems to hide nothing (which it would have on No. 2002).

Foxy

 

Speaking from a design office perspective, I would speculate it is a near certainty that Gresley would have looked over final and draft drawings and "red-penned" (pencil/crayon for 1930's?) anything he wanted changed. I doubt much would have escaped his eye. The draftsman would have had limited design authority.

I don't imagine much has changed drawing/design office wise, bar we now do our designs on computer and can make instant component and assembly changes. Someone still looks over physical drawings/designs and they go through review where seniors can pitch in their 2 pence/add red highlights!

While we are on drawings, why not auction/sell some of the drawings of P2 as an additional fundraiser? I would happily pay to get a nice A3/A1 size print of the P2 in profile. Do some wireframes/assembly dwg's, print them on some vellum paper...

 

Either theres something behind it that needs that extra height t0 be cleared, or the grand sweep you would see at the front of an A3 would have made the loco even longer. Suspect mostly the former perhaps part of the swing link housing?

 

Mmm.... the swing link is behind the drop mostly and the P1 (which also has a swing link) didn't need the extra deep buffer plank so it must be a style decision.

Fascinating to speculate after all this time!

Foxy

 

Trucks with side control by swing link (which were more common globally, as were swing link bogies) are no more bulky than trucks with side control by coil springs. There are various pics of the swing link truck on S160 1631 on their facebook page, which is a fairly typical example.

 

a P1 isn't on 4 X 6ft 2 inch wheels giving such a long loco, so the chances are the middle engine is mostly behind the swing link, suspect on a P2 where the middle engine is quite high and the swing link is partly below it and almost at the very front of the loco. Unless someone beets me to it - think ive got a GA drawing for this somewhere so see if that sheds any light.