So what shall we name the new P2?

[Dave]

Quite agree, does anybody know why they were not used out of Kings Xduring WW11

[S.A.C. Martin]

From everything I have read on the LNER during WW2, fuel efficiency was at their foremost concern with their locomotives during the second world war.

The P2s reputedly burned somewhere between 65-90lbs of coal per mile (dependent on your sources - O.S. Nock, Cecil J. Allen, D.W. Winkworth or Peter Grafton) which was still at its lowest reported average 15lbs higher per mile than the A4 and A1 pacifics of the time. They had repeated problems with hot axleboxes - well publicized - and were by virtue of reputation (not necessarily fact) track spreaders on the rails between Edinburgh and Aberdeen (a route known for rather tight curvature!)

So Thompson had more than ample justification for rebuilding them if we consider that a) reliability was an issue due to the repeated problem of hot axleboxes and b) the fuel efficiency of said units. The A2/2s in retrospect were inferior Pacific units to that of the A4s and A3s they joined, but their reliability and fuel efficiency were markedly better than the P2s as built, at a cost of not realizing their potential tractive effort due to lower adhesion (given the high power to weight ratio).

Bearing in mind the modern development of the boiler common to A2/2 and P2, and now the A1 Tornado, fuel efficiency is not necessarily the problem it was previously; however the question of the wheelbase and its route availability on the national network is still yet to be answered by either of the two groups definitively (though both have made it clear that this is not a problem which would deter them from building a P2 in some form).

[Atlantic 3279]

If you can't wait for the 12 inch scale version, have a look at this and scroll down the page to the sixth post:

loco-vans-brakes-workbench-another-cunn ... s1050.html

Track spreading (actual or alleged), hot axleboxes and heavy fuel use appear not to be adeterrent in seven and a quarter inch gauge!

[S.A.C. Martin]

If you can't wait for the 12 inch scale version, have a look at this and scroll down the page to the sixth post:

loco-vans-brakes-workbench-another-cunn ... s1050.html

Track spreading (actual or alleged), hot axleboxes and heavy fuel use appear not to be adeterrent in seven and a quarter inch gauge!

I would imagine the locomotive in question runs like a dream in seven and a quarter inch gauge, mind

[brsince78]

From everything I have read on the LNER during WW2, fuel efficiency was at their foremost concern with their locomotives during the second world war.

The P2s reputedly burned somewhere between 65-90lbs of coal per mile (dependent on your sources - O.S. Nock, Cecil J. Allen, D.W. Winkworth or Peter Grafton) which was still at its lowest reported average 15lbs higher per mile than the A4 and A1 pacifics of the time. They had repeated problems with hot axleboxes - well publicized - and were by virtue of reputation (not necessarily fact) track spreaders on the rails between Edinburgh and Aberdeen (a route known for rather tight curvature!)

So Thompson had more than ample justification for rebuilding them if we consider that a) reliability was an issue due to the repeated problem of hot axleboxes and b) the fuel efficiency of said units. The A2/2s in retrospect were inferior Pacific units to that of the A4s and A3s they joined, but their reliability and fuel efficiency were markedly better than the P2s as built, at a cost of not realizing their potential tractive effort due to lower adhesion (given the high power to weight ratio).

Bearing in mind the modern development of the boiler common to A2/2 and P2, and now the A1 Tornado, fuel efficiency is not necessarily the problem it was previously; however the question of the wheelbase and its route availability on the national network is still yet to be answered by either of the two groups definitively (though both have made it clear that this is not a problem which would deter them from building a P2 in some form).

Did I also read somewhere (and I may be totally mistaken) that the locomotives could not reliably negotiate the track curvature and pointwork in the loco depot at Kings Cross station??

[S.A.C. Martin]

Did I also read somewhere (and I may be totally mistaken) that the locomotives could not reliably negotiate the track curvature and pointwork in the loco depot at Kings Cross station??

Actually, quite the opposite. From everything I have read and inquired on, the P2s never had any problems negotiating the pointwork at King's Cross station. What did happen in BR days was the banning of several types of diesel locomotive - which could not negotiate the pointwork due to their frame designs, resulting in derailments and frame cracking!

It seems there is a very real difference of opinion as to whether the engines really did spread the track, or gain hot axleboxes from running against sharp curvature. O.S. Nock completely denies this was the case in his book, British Locomotive Performances, Cecil J. Allen "confirms" this suspicion but also states the often perpetuated thought of moving them down south to the King's Cross mainline (in his book British Pacific Locomotives), and Peter Grafton in his book on Edward Thompson gives a more balanced view, countering that the axlebox problem was present but that it was the mechanical reliability and heavy fuel consumption that led to their rebuilding as pacifics.

[Bill Bedford]

From RTCS Vol 6B:-
'''Rapid wear on the swing link pin holes resulted in the pony truck not functioning properly. Consequently the front coupled wheels took the task of of leading the the engine into curves and the outside crank pins on the coupling rods of these particular wheels needed frequent renewal. The P2's aslo had a particularly bad record of over-heated middle big-ends which was in part due to the stresses and strains at the front end from faults in the pony truck and to the enormous piston load of 34 tons.''' .... '''An over-heated middle big-end frequently resulted in the driving axle being badly scored and the middle connecting rod, piston rod, piston head and cylinder back being damaged. Sometimes the crank axle actually broke as a result of a big-end failure.'''
There follows details of three instances of such failures, the last on 10th April 1942. The passage then goes on :- ''' This seem to have been the last straw. At that time 2006 was already in Doncaster Works for new cylinders. It is perhaps significant that it was in April 1942 that the first outline drawing appeared showing the the P2's as they would appear after rebuilding as Pacifics.

It is worth pointing out that the swing link pony truck design was one of Gresley's patents. The problems of lubrication and wear were well know from its use on the K3's. Gresley had substituted spring side control for the swing links on his pacific bogies, but did nothing about the swing links on pony trucks. The V2's had their pony trucks replaced after WW2 after a series of accidents in which wear on the swing link pins was implicated.

It is entirely possible that the P2's would not have been rebuilt had Gresley paid a little more attention to the failings of his pony trucks.

[S.A.C. Martin]

From RTCS Vol 6B:-
'''Rapid wear on the swing link pin holes resulted in the pony truck not functioning properly. Consequently the front coupled wheels took the task of of leading the the engine into curves and the outside crank pins on the coupling rods of these particular wheels needed frequent renewal. The P2's aslo had a particularly bad record of over-heated middle big-ends which was in part due to the stresses and strains at the front end from faults in the pony truck and to the enormous piston load of 34 tons.''' .... '''An over-heated middle big-end frequently resulted in the driving axle being badly scored and the middle connecting rod, piston rod, piston head and cylinder back being damaged. Sometimes the crank axle actually broke as a result of a big-end failure.'''
There follows details of three instances of such failures, the last on 10th April 1942. The passage then goes on :- ''' This seem to have been the last straw. At that time 2006 was already in Doncaster Works for new cylinders. It is perhaps significant that it was in April 1942 that the first outline drawing appeared showing the the P2's as they would appear after rebuilding as Pacifics.

That's interesting Bill, none of the timekeepers make any mention of that, but Peter Grafton did (albeit briefly) in his book on Thompson. That's not well publicized in the railway press either!

It is worth pointing out that the swing link pony truck design was one of Gresley's patents. The problems of lubrication and wear were well know from its use on the K3's. Gresley had substituted spring side control for the swing links on his pacific bogies, but did nothing about the swing links on pony trucks. The V2's had their pony trucks replaced after WW2 after a series of accidents in which wear on the swing link pins was implicated.

It is entirely possible that the P2's would not have been rebuilt had Gresley paid a little more attention to the failings of his pony trucks.

It's interesting to note that when Thompson took over he turned his attention to replacing the Gresley pony trucks and swing link bogies before accidents happened (I think a single V2 and the W1 incident at Peterborough aside).

[manna]

G'Day Gents

All this is a fine debate, but to me still leads back to being the wrong class on the wrong bit of track, if they had been used on the 'flat' GN lines there coal consumption 'should' have gone down and running along comparatively straight track 'should' have lessened the front axle wear, even with a 'dud' pony truck.

manna

[Blink Bonny]

Ay up!

Given your LNER rating at this point in time, I would expect no other from you, Manna! I'd love to see one in 12 inch to the foot scale, if only to see if she could disprove the naysayers. Especially with that gorgeous open front.

I aspire to P2 rating - I may give up posting when I get there, unless Richard can grant special dispensation for me to remain thus?

[manna]

G'Day Gents

To me one of the most beautiful locomotives, ever to run on rails anywhere in the world, and the sooner we get a New one the better.

I'd love to see one pound up Stoke with 25 on, just to see if it could be done

manna

PS. The P1's look pretty good to.

PPS, pity we could'nt use the 'spare' Flying Scotsman boiler to rebuild a P1 any spare 8F chassis's laying around !!!

[S.A.C. Martin]

I'm in no doubt that a modern P2 with roller bearings throughout, the same boiler as on Tornado, with caprotti rather than poppet valve gear, and a new and improved design of front pony truck, would be a beast of a locomotive, and - should the A1 Trust decide to build one - would happily support it. But I think there's more to the P2 story than meets the eye, and Bill's timely comment should at least remind us that the class were not infallible as the timekeepers of the day would have us believe (Nock, Allen, Winkworth etc).

[Marvin]

PPS, pity we could'nt use the 'spare' Flying Scotsman boiler to rebuild a P1 any spare 8F chassis's laying around !!!

A referance to the infamous 48518 I take it - would it really be possible to use the remains for building a P1?

[manna]

G'Day Gents

Yep, was a bit of a swipe !!But in this day and age if we can build an A1, surely a P1 is possible, with a collection of spare parts !!!!!!

manna

[S.A.C. Martin]

Interesting note on the front end of the possible no.2007 from the A1's website:

Cylinders and valve gear: The idea to model No. 2007 on Cock o’ the North meant that rotary valve gear was preferable. Some changes may be made to the proportions of the cylinders to compensate for the increased boiler pressure available from the 250lb/sq in diagram 118A fitted to Tornado. However, the Lenz gear used on the original offered only limited cut-off settings and may have contributed, in part, to No. 2001’s high coal consumption. The Trust is therefore actively considering British Caprotti valve gear using a derived drive for the centre cylinder. This valve gear was perfected in its application to No. 71000 Duke of Gloucester and offers infinitely variable cut-offs, although the 71000 SLT is still developing and refining the gear.

Derived drive for the centre cylinder - Thompson-esque!

But it makes perfect sense, given the previous experience with Tornado, and hopefully whatever can be gleaned from 71000's palpable success story in preservation.