P2 Locomotive Company and related matters

Yes, I did state ‘flexible’.

 

Firstly to clarify things, the large hemispherical 'Heads' are the flexible stays, the smaller ones are the rigid stays. Now obviously the design is approved as suitable for purpose, although I imagine that once again the compliance is with the P2 (or A1?) group(s) personally I find the stay layout a bit unusual in that there is something of a 'mix' of stays on the backhead, as has been noted 3 columns of flexibles on the left and 4 on the right. but further down there are rigid stays surrounded by flexibles, and vice versa, it will certainly be interesting to see how this boiler 'Performs' in practice, I imagine that the U section foundation ring gives more flexibility than a solid ring, but whether this is desirable or not I honestly don't know.

 

From memory, is it not that the channel found rings are drop forged? the ones in the corners do see a lot of load.

Just spotted the assymetric staying. That is surely a mistake...? Unless the firehole door is non-symetric, i dont see why you would do this....? Is it a mistake on build....?

Well, even more reason not to steam that boiler in any way before necccessary. Youd be nearly at your 10 year ticket by the time the running gear was finished.

Deeply unwise to fit anything before the deisgn is frozen.

 

The amount of gear, ready for install, is quite large, from our last visit, interesting to know that the B17 crew, have new cannon box, maybe the extra that was being cast for the P2 is at hand.
Once the front bogey is in, block valve gear agreed, then fitted, this video by the late David Elliott is worth a look.

David Elliott talks about the P2 cylinder monobloc.

 

Oh, there is a lot more work left than I had realised.

Is the valve gear desgin actually frozen yet?

 

Never seen that... what a piece of engineering and so sad David will not be around to the finale. Many, many thanks... that's made my day.....

 

Beautifully produced video and well worth studying David Elliots commentary being very clear and precise for this impressive piece of real new building. I would like to think that in future things such as boiler manufacture (Which is a much 'simpler' branch of engineering) is taken 'In house' or at least back in Britain, thus reducing the inconvienience that this group and other true new builders have or may have had.

 

@Sheff would be the one to comment, last I heard on here was a working 3D printed model was to be made to prove operation.
Nobody is sure if that has happened yet.
To be fair, the trust said recently that work was re-commencing, after the mainline connection was completed, basic wins like building the kit of parts for the tender have been accomplished.
If i get the chance I may go down to Darlington tomorrow, and see if I can some pics, they may be of a bit more use.

 

Looking at the pictures, the foundatio ring doesn't look to be a U shape, a la Bulleid light pacific. It could be a built up channel section, though.

 

I agree Steve, it doesn't look like a U shaped "foundation ring" - it looks more like the foundation ring on Tornado's boiler when it returned from Germany in 2011 after its first overhaul as seen here


Peter

 

I must admit that it does look like a square ring, probably channel. Tornado.s 2011 boiler certainly has fewer flexible stays than the p2's so hopefully a lesson has been learnt, BUT that welding on the corner of Tornado's foundation ring? having looked at German boilerwork I've no doubt that it's well up to their standards, but my inspector would have a pink fit it it was presented to Him.

 

That picture makes a very interesting comparison with what has just been delivered to Darlington. The difference in the number of flexible stays on the blackhead is startling, presumably the result of an experience curve?
I'd like to know more.

 

In response to posts above, firstly let’s just recap the boiler history….

Here’s my post from June 24 comparing the various iterations of Tornado’s boiler …
https://www.national-preservation.com/threads/tornado.10750/page-375#post-2880614

In more detail from the Trust’s website …..

Feb 23 - Tornado’s refurbished boiler
https://www.a1steam.com/tornado/news/tornado-details/tornado-a-boiler-update

Sept 23 - P2 boiler - maybe the one that has finally been delivered, though staying is different? https://www.a1steam.com/tornado/news/tornado-details/p2-boiler-latest

Regarding the foundation ring, the corner design was changed some good while ago in 2014, following several cases of cracking. The later design is forged, so the grain of the metal curves with the corner.
https://www.a1steam.com/tornado/news/tornado-details/forging-not-cutting-corners

As for the status of the valve gear, @guycarr360 is rather too generous in referencing me as a reliable source these days. I haven’t been up to a Darlo since Covid, (but nothing to do with the virus), and other than the Trust’s own bulletins I have to rely on my contacts now.

I’m trying to remember if the 3D printed model was ever produced ….. I’ll do some searching …
…. yes it was, by David Elliott. See page 6 here ……
https://www.a1steam.com/Portals/0/VGC MAR 2024 REV 8pp_WEB.pdf

More importantly, the item also describes how a full scale prototype rig is to be produced in the metal and run at length to prove the reliability of the design.

To my knowledge this is still not complete. Without this critical design development stage being successfully completed I think it would be very rash to mount the boiler, maybe even the cylinders themselves?

 

This discussion was a bit over my head, but I learned finite element analysis as a young engineer, and I have just done a search and found this webpage: https://www.consuta.org.uk/workshop/FEA.html

Presumably, the boiler under discussion was designed by rule and checked by FEA?

I can see no reason at all why there should be an asymmetry on the backhead. Can someone explain?

 

Good man... keep it coming....

 

Very interesting link, particularly as I was involved in the museum service at the time that 'Consuta' was re-boilered about 2002, the boiler in 'Consuta' is roughly the size of a small steamroller boiler. It was interesting to see the barrell sections moving in a way that suggested 'Collapse' .Longitunidal expansion on boilers is an interesting thing, one 0f mine being of all rivetted construction expands around 1/8" in 4' whilst a larger, half rivetted (original component) and welded (1970's replacement) hardly expands despite being around 2' longer. I do know the reason but it is hardly relevent to the present discussion.

 

Boiler and cylinder mounting.. surely just a trial check that they actually fit... David Elliott mentioned a "tight fit" in the video?

 

Sure, nothing wrong with a trial fit, though if iirc there’s no overhead crane in DLW2, so need to hire in a mobile one?

 

Can someone remind me - is the boiler just delivered (with the assymetric pattern of stays) an entirely new one, or an existing boiler refurbished?

(I'm losing track).

Tom

 

It ‘brand new’ though how many iterations there’ve been during its construction is open to question. See the Sept 23 article vs what’s landed in Darlo.