P2 Locomotive Company and related matters

I think a better term might be "adequately" - there is argument that had not the number of Lentz fitted D49s been so high, and WW2 intervened, they would have all been rebuilt as walschaerts fitted examples. There's certainly not much to choose between the two sub classes historically.

 

deleted

 

The Franklin gear is closer to the reidinger gear fitted to half a dozen Crabs than the prewar Lentz. Indeed only the willingness to refine the caprotti to a more acceptable solution(i.e the last two black 5s) again postwar together with a bit of golf course diplomacy got the caprotti on the Standards but both BR Caprotti and Reidinger were a lot more advanced than prewar versions...

 

Yes, he did build them in all three gauges, starting with the largest. He also built a standard class 5 in 5" with Caprotti gear.. Apparenty he built quite alot of the 7.25" gauge one in a remote part of Nigeria with quite limited equipment.

 

The LNER experimented with valve gears rather more than an outsider might think. In 1926 Lentz poppet valves were fitted to an ex-GER 4-6-0. These were driven by Stephensons gear and were of the oscillating cam type. Six more engines were converted between 1928 and 1930 and based on the reports that the early conversions ran noticeably increased mileages between repairs than their piston valve fitted contemporaries a new batch of ten B12s were built in 1928 fitted with the new gear. As with so many things the first impressions deceived. Drivers complained and inspectors sallied forth. There were mechanical issues including cylinder cracking and the engines were found to be seriously lacking when it came down to the ability to climb the steeper grades. A return to piston valves was ordered.

Some observers maintain that the GCR 4 cylinder 4-6-0s were rather poor engines with very high fuel consumption. Others, including the late Dick Hardy would have none of it, what was needed was a driver that understood how to use them. In 1929 two of the B3 class were fitted with Caprotti gear, numbers 6166 and 6168. this gear, supplied by Beardmores, was identical to that used on some Claughtons by the LMS. In this gear the valves were spring operated and the design was basically as Arturo introduced it in 1922. The springs did weaken under the action of high temperature steam and there were breakages. The cam operating scrolls were originally cast iron and these also failed but the application of bronze scrolls solved this problem. These two engines were reportedly low on maintenance and were well liked. Some arrangement was needed to help with air flow to help to keep the cam boxes cool. The Caprotti fitted engines were between 9.6% and 15.65% improved in fuel consumption when measured over 1931 - 1934 depending on whether they were working in the same link or otherwise.

Trials were organised in March 1936 between 6166 and the piston valve fitted 6169 using the same grade of coal over the same route. here the Caprotti fitted engine had a 21.9% advantage.

Though we have lbs/mile figures and details of the load and route we have no figures for fuel per unit of power output. But Gresley ordered two further conversions, 6164 and 6167, and these took place in 1938. These two engines had a revised gear fitted. Steam operation of the valves replaced the springs and the cam boxes were strengthened with harder wearing surfaces and better oil seals.. These engines were also well liked and an enthusiastic Woodford shed master set about recording much detail of their performance. However WW2 washed all this work away. The LNER learned enough from the two sets of conversions to realise that the second pair were much superior and they set about a third design which amongst other things addressed the issue of excessive clearance volumes with the intention of converting all the B3 and B7 class members.

Excess clearance volumes was a problem on the B3 conversions and also on 2001 but in terms of mechanical dependability it appears that the LNER were making progress. The B3 conversions, particularly the second pair, appear to have performed rather well, certainly better than 71000 which has been beset by peculiar valve issues more than once. Possibly the LNER had an engineering team that was far better than its rather poor financial status would suggest.

 

Some news from the Doncaster P2 Locomotive Trust, "cock`o the north"

https://www.cockothenorth.co.uk/supporting-us/founders-club/

They have also set up a crowd funding page:

https://l.facebook.com/l.php?u=http...5MxYa5U9N4Z6n4_yRrKBp2iiqxiK3bUB3tGq3PPsKXaHg

Knut

 

Is this a better thread for the Doncaster P2?

https://www.national-preservation.com/threads/2001-cock-o-the-north-help-required-please.512641/

 

Sadly, Brian Blessed notwithstanding, I fear that this project is a VERY long term one, especially given how the 2007 build has so speedily progressed.

 

A friend of mine had kindly arranged for 3 of us to visit the P2 facility at Darlington Locomotive Works today. 2007's wheels had been moved out for further work including the fitting of balance weights, but the whole appearance of this locomotive is, in my view, simply awesome, even without its tender, work on which is planned to commence next year. The whole operation is most professional and there is no doubt in my mind that 2007 will roll out in full working order in 2021 if we all support the scheme. We were very grateful to Lee for showing us round and, I was so impressed, I have decided to sign up and join (I can't believe it really as this is no Swindon loco!). I'll just have to cut down on beer but it will be worth it!

We also visited the nearby Darlington Railway Museum ("Head of Steam") at the old North Road Station. As it was my first visit I was very glad to go but, as it's Halloween, or something, soon, they had festooned most of the place with "spooky tat" which didn't help photography!

 

More exciting news from The P2 Project!

https://www.p2steam.com/category/news/

Knut

 

"Re-routing the steam and exhaust passages to physically separate them to prevent incoming steam from heating the outgoing exhaust"

Surely that is the wrong way around from a thermodynamics perspective, to prevent incoming steam from being cooled by the outgoing exhaust seems more logical no?

Post Weld Heat Treat (PWHT) is going to be interesting on this, its a big old block with a lot of welds.
Do you do an intermediate PWHT or stick it all together and hope you can get all the residuals out at the end?

I say this in the light of the recent Tornado findings of bore concentricity/angularity/tolerance stack.

There is a big incentive to get the residual stresses out of this fabrication as much as reasonably practicable to ensure the required geometry is stable and envisioned tolerances are achievable.

A pre-weld heat up probably a good shout too.

Is that a simplified saddle model for sake of ease or is it going to be that shape?

 

It's the same thing whichever way you say it - heat transfer from the live to the exhaust steam sides.

 

Entropy, entropy, they've all got it entropy …

Tom (with apologies to Kenneth Williams, and indeed my thermodynamics tutor

 

And apologies to Kenneth Williams too?

 

Him as well

Tom

 

A line originally uttered by Jimmy Edwards.

 

P2 looking rather good on the cover of this month's SR:

https://www.p2steam.com/2019/01/04/latest-steam-railway-cover/

 

Yet another 'Exclusive', I note.

 

Is it not?

 

Did I hear someone sharpening an axe....?