P2 Locomotive Company and related matters

I wish them good luck.. £5mn is a great sum to achieve.

Are they being over cautious or are the other new builds just being unrealistic ?

Not as many liveries to offer a P2 in.

 

Th'all save 15% in coal wi' 3 sets o' Caprotti on there- a truly 'green' engine!

 

Interesting news. Dare I bring up the question of what it is to be called ? 60163 got its name quite early as its easier to manage and generate public support around a loco name as a brand. Presumably the P2SLC will do the same ?

 

I believe that a name is to be revealed in the New Year

 

I would'nt be surprised if they painted it BR livery at some time ,but what number would it be given ? Anyway good luck to the project .

 

If it was in BR livery, presumably 60507 - the P2s were renumbered by Thompson 501-506 after his butchery, and this would be the next one. Mustn't let anyone think that there was another K1 on the loose. But I do prefer the A4 front end....

 

There is nothing wrong with the Gresley/Holcroft gear kinematically. There are two problems - the middle valve is more difficult to set and wear in the gear results in the middle cylinder doing more than its fair share of work. This led to big-end failures - not that the middle big end itself was an especially brilliant design . It's also possible that frame flexing and differential expansion had some effect on the Gresley exhaust beat.

It is not the only valve gear arrangement that produces unequal effort from the cylinders. Coupled with minor geometric and physical variation almost all steam engines produce more power on the backward stroke of the pistons than the forward, and inside cylinder gear on large locos has its own set of problems. Anyone who remembers the OneTWOthreefour beat of the LNWR G2's will realise that an even beat is not a necessary feature of steam loco design.

At least the Gresley gear itself was easy to maintain, and made the rest of the loco easier to maintain than other multi-cylinder designs apart from the big end.. The performance of all the Gresley large engines proves that they were not in any way hampered by the gear, except maybe in starting a heavy train from rest. Modern train length limitations will mean that certainly won't apply to a P2!

Two possible modifications could be made - roller bearings at every joint and a sturdier big end that accepts that the middle cylinder will sometimes produce more than its designed power.

 

Maybe that 'wrecker' Thompson wasn't so daft 6 useful locos made from the pampered Mikado not fit for wartime maintenance schedules, workers on 16 hour shifts, ironically, it may be those were rebuilds that helped win the war. No criticism of the pre war Mikado, but perhaps we should just comprehend the state we were in, 6 'new' lower maintenance pacifics that could load 20 coaches day in day out up the ecml more economically- they might have made a difference to all of us and deserve recognition. In 1943 they were what ecml needed completely. Now bring back the Mikado for peacetime!

 

60507 (LNER 3696) was, of course, "Highland Chieftain", another Thompson abortion, assembled from the bits ordered for the last batch of V2's.

On the subject of conjugated valve gear:
The uneven beat of the Gresley 3-cylinder exhaust has little to do with the valve gear or crank settings, but is due to the rearward position of the inside cylinder, with its shorter con-rod. The exhaust pipe, particularly from the back port, is considerably longer than those of the outside cylinders, and it, therefore, takes longer for the inside cylinder exhaust to reach the blastpipe and be heard. This is eloquently explained by Rudi Rindlhardt, of VES-M Halle and Aw Meiningen fame, on his treatise on DR 18 201, which has a unique exhaust beat, compounded by the use of a Giesl ejector.

 

Just skim Tornado's first 10-year off the excess

 

I don't dislike Thompson. The B1's were sorely needed. And the K1's and O1's were good designs too. But his Pacifics were failures, in significant part due to the measures he took to avoid using the conjugated gear, and the P2 rebuilds the worst of the lot. Look at the tiny mileages they achieved after rebuilding and you can see how useful they were.

I don't want to derail the thread into a Gresley vs Thompson discussion, because most of those discussions forget entirely the various financial and political constraints that they had to work with. If Gresley had been fully able to build what he had wanted, the J39's would never have been built, and you'd have had something like the K1 in the late 20's.

 

Not absolutely necessary perhaps, but certainly highly desirable.

According to Cook the primary problem with the big end was poor lubrication

 

And according to Harvey they were not sturdy enough, and once deformation occurs due to stress or wear lubrication failure is inevitable...

 

All the Gresley pacifics had a redesigned big end after WW2, as described by both Peter Townend and Bill Harvey. Tornado has that design of big end so I'm sure that aspect of the design will be well catered for.

 

Why? There's no need. Actually, a loco with four absolutely even beats is rare, and Garatts of course go in and out of sync without any harm. Mind you, the most even beat I've ever heard was Leander working hard on a railtour back in 1974 or thereabouts, a fabulous sound.

 

Or even 6....

 

But Garratt's going out of sync is a totally different thing to uneven exhaust beats on a non-articulated loco. It's effectively no different from the exhaust beats from a pair of Black 5's double heading.

 

Well the 'Gresley Beat" didn't seem to hinder the A4s etc. so perhaps a wholly even beat wasn't as important as some make out.

 

But the beats from two black 5s are drawing two fires not one as in the case of a Garratt.