hornby 2020 Hornby A2/2 and A2/3 (2020 Range)

[davidw]

22 minutes ago, robmcg said:

 

Yes sorry I was just correcting that with an edit when you wrote your post... the pic is NOT as it will be in production, it is nearer 60501..  My apologies.

No problem, I really appreciate all the photoshoping stuff you do a real art form.

[robmcg]

Thanks, and in the spirit of 'approximately' , here are 60501 early crest, forward dome, separate sand filler covers, and 6505 again this time with rearward dome, large filler cover, and so on.

 

There is a photo somewhere of 60505 with late crest and forward dome but stovepipe chimney somewhere, you can't win!

 

Hornby certainly have done a lot of work, with Tony Wright's input, and the review running on Little Bytham, we have something nice to look forward to...

 

 

[davidw]

1 minute ago, robmcg said:

Thanks, and in the spirit of 'approximately' , here are 60501 early crest, forward dome, separate sand filler covers, and 6505 again this time with rearward dome, large filler cover, and so on.

 

There is a photo somewhere of 60505 with late crest and forward dome but stovepipe chimney somewhere, you can't win!

 

Hornby certainly have done a lot of work, with Tony Wright's input, and the review running on Little Bytham, we have something nice to look forward to...

 

 

Indeed it will. I'm sure the A2/3 will too. There's many many detail differences in the A2/2 I'm surprised and delighted that it's been made. Capturing the details is excellent.

[atom3624]

It looks a stunning model.

Pity the real thing was such a disaster!!

 

Why were the P2's rebuilt?

 

Al.

[robmcg]

2 hours ago, atom3624 said:

...

 

Why were the P2's rebuilt?

 

Al.

 

Do you have a few hours to spare?

 

When Sir Nigel Gresley died suddenly in 4/1941 his deputy CME Edward Thomspon became CME of the LNER. The P2s were judged by many to be hard on track and not fully developed, opinions vary, and for whatever reason they were not deemed suitable for general ECML work at any time in their careers.

 

Thompson wanted quite sensibly in wartime to have standardised designs with low maintenance, e.g. rocking grates, and Gresley's conjugated valve gear was not thought ideal either, but Thomson also appeared to want to prove points against Gresley; he discarded conjugated valve gear, changed the regulator and cut-off controls from what engine crews were used-to, he insisted on equal length connecting rods for inside and outside pistons, creating a long wheelbase prone to cracking, and not very forgiving for ride at speed, in short, the A2/2 design was experimental.

 

Wartime  put tremendous pressure on the railways, skilled staff were short, and Thompson's O1 and B1 designs worked well.  His A2 designs were quietly being re-designed by workshop draughtsmen so Peppercorn was quickly able to replace them after Thompson retired.

 

Thompson's people skills were not overly great, nor in my opnion his fundamental design skills, and in the circumstances the decision to rebuild the P2s into powerful Pacifics looked ok on paper... but....  as I say, how long do you have?

 

A 50 sq ft grate on a hand-fired engine?  Chapelon had already shown this to be no more than a way to waste coal...

 

Very interesting engines nevertheless, and others know a lot more than I do!

Edited December 15, 2020 by robmcg
typo

[atom3624]

Thanks for that Rob, was interesting enough.

 

I do remember the mention of the P2's running hard on the rails.

 

I suppose in development, it can take a while to 'fine tune' the final product.

 

Al.

[Rshakes3]

Thanks team, just to add a little more to this, from what I`ve read the P2’s also had pony truck, driving axal failures and cracking frame issues. So remember their prime reason for being was to lift the heavy Aberdonian up from Aberdeen pre war.

That line was heavily graded and had tight curves which did not really suit a loco with a long fixed wheel base. From what I understand it was also found that the pony truck was not really doing its job and hence the front drivers were doing a lot of the guidance work – hence the frame cracking.

Faced with these issues in mid war they were rebuilt with the aim of addressing these issues – as Rob has outlined – however I have also read that they could have been relocated to Kings Cross to work the ECML where the grades and curves were far less constricted and the above issues would have been mitigated. Their power would have been a significant advantage against the A1/A3/A4 which were being pressed hard with the increased train lengths at that time.  If that had happen they may well not have been re build -  So something more to ponder  

[robmcg]

1 hour ago, Rshakes3 said:

Thanks team, just to add a little more to this, from what I`ve read the P2’s also had pony truck, driving axal failures and cracking frame issues. So remember their prime reason for being was to lift the heavy Aberdonian up from Aberdeen pre war.

That line was heavily graded and had tight curves which did not really suit a loco with a long fixed wheel base. From what I understand it was also found that the pony truck was not really doing its job and hence the front drivers were doing a lot of the guidance work – hence the frame cracking.

Faced with these issues in mid war they were rebuilt with the aim of addressing these issues – as Rob has outlined – however I have also read that they could have been relocated to Kings Cross to work the ECML where the grades and curves were far less constricted and the above issues would have been mitigated. Their power would have been a significant advantage against the A1/A3/A4 which were being pressed hard with the increased train lengths at that time.  If that had happen they may well not have been re build -  So something more to ponder  

 

Indeed, I never did work out why the P2s were kept away from the ECML. 

 

Best,

[robmcg]

Actually one wonders why the Scotland based P2s were not thought of as useful on those very heavy wartime trains on the ECML... maybe that was AFTER the decision had been made to rebuild them. And on paper the rebuilds should have been better than they proved to be in practice.

 

Presumably the likely high maintenance and non-standard nature of the P2 mitigated against them, too?

[atom3624]

A2/2 looked impressive in the latest Signal Box.

 

Couple of observations of mine:

Perhaps the effect of the video, but the quartering appeared slightly out - rear wheel 'dragging' behind the fronts, looking a bit like a Mexican wave despite the smoothness!!

Don't think the full sized one would have had a gap under the mini-deflectors as seen .. hopefully they'll get a more-flush mounting for production.

 

Al.

[landscapes]

Hi 

 

I see that the pending W1 Hush Hush availability dates have been put back to Spring/Summer 2021.

 

Has anyone any idea on delivery dates for the A2/2's and A2/3's?

 

Regards

 

David

[davidw]

On 20/12/2020 at 18:32, landscapes said:

Hi 

 

I see that the pending W1 Hush Hush availability dates have been put back to Spring/Summer 2021.

 

Has anyone any idea on delivery dates for the A2/2's and A2/3's?

 

Regards

 

David

Apparently "Cock of the North" is imminent? The others about 6/8 weeks behind.

[landscapes]

1 hour ago, davidw said:

Apparently "Cock of the North" is imminent? The others about 6/8 weeks behind.

Thanks David

 

Thats the only Hornby Thompson I have ordered 

 

Regards

 

David

[Headstock]

On 16/12/2020 at 20:54, robmcg said:

Actually one wonders why the Scotland based P2s were not thought of as useful on those very heavy wartime trains on the ECML... maybe that was AFTER the decision had been made to rebuild them. And on paper the rebuilds should have been better than they proved to be in practice.

 

Presumably the likely high maintenance and non-standard nature of the P2 mitigated against them, too?

 

Good evening Rob,

 

the LNER would have never allowed the P2's to operate on heavy wartime trains, at the southern end of the east coast mainline. It is now known that the LNER new they had a serious problem with the design of the crank axle on the P2's. The design was basically the same as that used on the A3 pacific without any problems. However, the P2 could develop significantly more torque than the A3. In addition, the four axles produced a more sure-footed locomotive, that was very difficult to make slip. Unfortunately, the crank axle wasn't up to the job of resisting the additional force that the loco could supply.  That force could not be dissipated by the locomotive slipping, as would be the case with a pacific.

 

So far, six  crank axle failures have been discovered by researchers, with more suspected. This is an unacceptable amount, amongst a small class of locomotives over a short period of time. Indeed evidence of creeping damage existed on the crank axles of all the locomotives. It was noted that the crank axle failed as the locomotives were accelerating away from a stand and a point were that maximum torque was being developed. The locomotives were effectively damaging themselves every time they had to pull hard. The possibility existed that the crank axle could have failed at any time due to the accumulation of damage. The LNER's own photographs show that a crack started at a sharp edge of the key that held the axle in place and spread across the axle until about two thirds of the way across, then it snapped off, very frightening. 

 

The pony truck was the main issue with the track on the Aberdeen road, this could have been sorted in a similar fashion to that applied to the V2's. The crank axle was another issue altogether during wartime conditions and scrapping was even considered. The compromise was to restrict the loads that they worked, which kind of defeated the point of them. Thompson was asked to look at the problem, he sent the rebuilt Hush Hush locomotive north to try it out on the P2 workings, it was very successful. The result of this was that it was felt that the extra power provided to a Pacific, with by a 50' grate, would be an the ideal solution to the problem. 

 

The new build P2 has a new design of crank axle.

Edited January 15, 2021 by Headstock
add info

[rembrow]

On 20/12/2020 at 18:32, landscapes said:

Hi 

 

I see that the pending W1 Hush Hush availability dates have been put back to Spring/Summer 2021.

 

Has anyone any idea on delivery dates for the A2/2's and A2/3's?

 

Regards

 

David

Yesterday's Kernow Models weekly newsletter advised that they are expecting the A2/2s by the end of the month. Presumably this is from Hornby trade info.

[robmcg]

On 15/01/2021 at 13:55, Headstock said:

 

Good evening Rob,

 

the LNER would have never allowed the P2's to operate on heavy wartime trains, at the southern end of the east coast mainline. It is now known that the LNER new they had a serious problem with the design of the crank axle on the P2's. The design was basically the same as that used on the A3 pacific without any problems. However, the P2 could develop significantly more torque than the A3. In addition, the four axles produced a more sure-footed locomotive, that was very difficult to make slip. Unfortunately, the crank axle wasn't up to the job of resisting the additional force that the loco could supply.  That force could not be dissipated by the locomotive slipping, as would be the case with a pacific.

 

So far, six  crank axle failures have been discovered by researchers, with more suspected. This is an unacceptable amount, amongst a small class of locomotives over a short period of time. Indeed evidence of creeping damage existed on the crank axles of all the locomotives. It was noted that the crank axle failed as the locomotives were accelerating away from a stand and a point were that maximum torque was being developed. The locomotives were effectively damaging themselves every time they had to pull hard. The possibility existed that the crank axle could have failed at any time due to the accumulation of damage. The LNER's own photographs show that a crack started at a sharp edge of the key that held the axle in place and spread across the axle until about two thirds of the way across, then it snapped off, very frightening. 

 

The pony truck was the main issue with the track on the Aberdeen road, this could have been sorted in a similar fashion to that applied to the V2's. The crank axle was another issue altogether during wartime conditions and scrapping was even considered. The compromise was to restrict the loads that they worked, which kind of defeated the point of them. Thompson was asked to look at the problem, he sent the rebuilt Hush Hush locomotive north to try it out on the P2 workings, it was very successful. The result of this was that it was felt that the extra power provided to a Pacific, with by a 50' grate, would be an the ideal solution to the problem. 

 

The new build P2 has a new design of crank axle.

 

A very interesting and informative post, thankyou Headstock.

 

Given the pressure to supply working engines during and immediately after the war it is no surprise that the rebuilds were approved, shortcomings notwithstanding.

 

Imagine the post-war furore if all six P2s had been scrapped!

 

I still think the Thompson A2s were hamstrung by his insistence on equal length connecting rods.

 

And rebuilding Great Northern as he did was evidence of poor judgement.

[railroadbill]

Headstocks post on the P2 problems was very interesting. Re the rebuilt locos, it was wartime when the Thompson rebuilds took place, so anything that cut down maintenance and improved reliability was crucial.  Also the A2/2s were a good tryout for the A2/3s. Just been reading CJ Allen's book British Pacific Locomotives and he makes the point that both A2/2 and A2/3 had a very good front end design and were very fast locos. He includes a log of a run from York to Darlington with 60502 which he said was the fastest he had ever known on that line. 

Interesting looking back on what is a rather long time ago now.

I've now got a Hornby A2/2 on order....

[robmcg]

43 minutes ago, railroadbill said:

Headstocks post on the P2 problems was very interesting. Re the rebuilt locos, it was wartime when the Thompson rebuilds took place, so anything that cut down maintenance and improved reliability was crucial.  Also the A2/2s were a good tryout for the A2/3s. Just been reading CJ Allen's book British Pacific Locomotives and he makes the point that both A2/2 and A2/3 had a very good front end design and were very fast locos. He includes a log of a run from York to Darlington with 60502 which he said was the fastest he had ever known on that line. 

Interesting looking back on what is a rather long time ago now.

I've now got a Hornby A2/2 on order....

 

I'm still trying to work how many of the shortcomings of the A2s were from things which could have been and should have been fixed, like the poor ride at speed, dangerous hunting at 90mph according to some, and discomfort above 60mph... traced to inadequate front bogie side-control combined with frame length.  Same bogie was ok on B1s.

 

That shortcoming alone would make the engine unpopular with crews.  On top of that the cutoff and regulator controls were different from Gresley style....  and there were few A2s on any roster, I can just imagine the groan if you signed on and got an A2 instead of an A3...particularly an A3 in good nick, and a typically heavy train with fast schedule requiring 70mph+

 

And Thompson had for whatever reason chosen to rebuild Great Northern in Thompson style rather than leave it for conversion to A3... and got rid of wedge cabs, and generally wasn't liked much, I tend to go with the rather low opinion of Thompson's people skills, but am still curious about the A2 and 'there but for a pennyworth of tar' reputation  ?

 

The new models do look irresistible in terms of modelling excellence, I will HAVE to buy one!  

[9402 Fredrick]

2 hours ago, robmcg said:

 

I'm still trying to work how many of the shortcomings of the A2s were from things which could have been and should have been fixed, like the poor ride at speed, dangerous hunting at 90mph according to some, and discomfort above 60mph... traced to inadequate front bogie side-control combined with frame length.  Same bogie was ok on B1s.

 

That shortcoming alone would make the engine unpopular with crews.  On top of that the cutoff and regulator controls were different from Gresley style....  and there were few A2s on any roster, I can just imagine the groan if you signed on and got an A2 instead of an A3...particularly an A3 in good nick, and a typically heavy train with fast schedule requiring 70mph+

 

And Thompson had for whatever reason chosen to rebuild Great Northern in Thompson style rather than leave it for conversion to A3... and got rid of wedge cabs, and generally wasn't liked much, I tend to go with the rather low opinion of Thompson's people skills, but am still curious about the A2 and 'there but for a pennyworth of tar' reputation  ?

 

The new models do look irresistible in terms of modelling excellence, I will HAVE to buy one!  

As stated before, he isn't liked because of garb said about how he was destroying gresley's legacy, even though if the P2s and Great Northern were on any of the other 3 railway companies they'd be scrapped, and like in the video posted a few pages back, a lot of stufd thompson did was also from research other people did, plus the conjugated valve gear was in terrible nick due to low maintainence during WW2, so heavy repairs had to be done to any 3 cylinder Gresley locomotive post war.

[9402 Fredrick]

Also, the P2s weren't actually as good in practice as they were on paper, the A2/2s actually saw more use than when they were P2s, but no one realized it as they were focusing on the "Thompson hates Gresley." nonsense, even to the point where they made it seem like Thompson was berating Peppercorn, the A2s were built to be mix traffic pacifics, but I'm guessing a lot of factors made it seem like his pacifics were the worst locos ever to be used on the Eastern & North Eastern regions of BR.

[Headstock]

15 hours ago, robmcg said:

 

A very interesting and informative post, thankyou Headstock.

 

Given the pressure to supply working engines during and immediately after the war it is no surprise that the rebuilds were approved, shortcomings notwithstanding.

 

Imagine the post-war furore if all six P2s had been scrapped!

 

I still think the Thompson A2s were hamstrung by his insistence on equal length connecting rods.

 

And rebuilding Great Northern as he did was evidence of poor judgement.

 

Good afternoon Robert,

 

I don't think that the rebuilding of the P2's into Pacific's was the right solution to the problem. The defects in the design were not terminal and could have been corrected, but  to what purpose? They would have still been a small class of locomotives that wouldn't have been propagated by either Gresley or Thompson. Thompson really wanted to build locomotives in relatively large numbers, that would for fill the roles that were currently done by multiple classes. There is a lot of Oliver Bullied in the P2's, I suspect that the want of an eight coupled locomotive pre dated the traffic requirements of the Aberdeen route, those requirements became a convenient excuse to build one. In reality, most of the services over the rout didn't require P2 power.

Critics of Thompson will point out that he created more classes of Pacific than his predecessor, however the A2/1 and A2/2 were really  test beds for his future standard mix traffic pacific. The problematic P2's were just a convenient way of getting such a locomotive built. The A2/2's were by far the worst of the bunch, the poor mechanical reputation of the Thompson Pacific's can be traced directly back to these locomotives.

The equal length connecting rods were not Thompsons idea,  though it is a feature of his old stamping ground on the NER. It was rather one of his underlings who pushed the benefits, though Thompson is ultimately responsible as CME. There is a theoretical advantage in having equal length connecting rods on three sets of valve gear, but in the grand scheme of things it isn't necessary. The problems of the A2/2 was not the connecting rods in themselves, it was the rather slapdash detail design of the front end, made necessary to accommodate them. Thompsons real obsession was with replacing the conjugated valve gear, there is no doubt that he over emphasised the problems with this, in order to pursue his own solutions that created there own problems.

A bigger problem was the large  cylinders, inherited from the P2. This necessitated the bogie being moved further forwards so that the wheels didn't strike the cylinders. If given smaller cylinders, the A2/2 could have retained a bogie position, more like the GWR Castle or the LMS Princess. That would have required a higher pressure boiler to offset the smaller cylinders and retain the tractive effort that was required. However,  writing off the P2 boiler was not going to be an option. The big cylinders caused all sorts of stress problems on the front end and contributed to the locomotives poor riding. The latter A2/3 class had smaller cylinders and a correspondingly higher boiler pressure , they had less problems with the front end and rode better. Inexplicably, they retained the bogie position of the A2/2 when it wasn't strictly necessary. 

Great Northern is an interesting tale in itself, as it was effectively, the only true development of the classic Gresley Pacific. It was basically an A4 with bigger cylinders. The rebuild was probably the most despised of the Thompson Pacific's, however, as a locomotive, it wasn't as bad as its reputation is often portrayed. it suffered mechanically like all the Thompson Pacific's but the concept of an A4 with bigger cylinders was actually a pretty cool idea. A Peppercorn version would have made an interesting comparison with the A1. In reality it was a dead end, all future LNER Pacific's would trace their lineage back to the P2.
 

Edited January 17, 2021 by Headstock
Add good afternoon.

[atom3624]

Interesting reading.

 

Question: Of the problems listed and implied above and previously, have these all been resolved in the P2 2007 PoW newbuild?

I believe I've read of using a higher pressure boiler, so does that mean the cylinders are smaller than the originals?

 

Al.

[Headstock]

1 hour ago, atom3624 said:

Interesting reading.

 

Question: Of the problems listed and implied above and previously, have these all been resolved in the P2 2007 PoW newbuild?

I believe I've read of using a higher pressure boiler, so does that mean the cylinders are smaller than the originals?

 

Al.

 

Good afternoon Al,

 

the simple Answer is yes, including it would seem the poppet valve gear that was such a problem on 2001 in its original condition. The boiler is identical to that fitted to 60163, the two will be interchangeable. The Peppercorn A1 boiler is the final development of the original P2 boiler. The working pressure is higher and this has allowed a reduction in the size of the cylinders, though they will be slightly larger than the cylinders on 60163.

 

The reason for this, is because of 60163's outstanding run on Beattock, were the locomotive passed the summit at 75 mph, with the safety valves still lifting. This indicated that the boiler had plenty of steam in reserve. The power output required to achieve this, has been calculated to have matched, or even surpassed, the maximum power out put ever recorded by a British steam locomotive. If a Dynamometer car had been attached, the official record would have quite possibly fallen to the A1. This is not a one off, the locomotive has unofficially come close to the record on a number of occasions. The only thing that restricted a greater effort from the locomotive on Beattock, was the size of the cylinders. They were not capable of using all of the steam that the boiler was generating. However, you wouldn't want to fit larger cylinders to a Pacific, as this would be detrimental to its factor of adhesion. There are no such problems with the P2, due to its eight coupled wheelbase. The calculation for 2007, using the same boiler as 60163 and slightly larger cylinders, would produce a maximum power output, some 17 percent greater than maximum output ever recorded. With some justification, 2007 can be claimed to be Britain's most powerful steam locomotive.

Edited January 17, 2021 by Headstock
clarify a point

[atom3624]

Interesting information indeed.

It's definitely not a competition with highly expensive potential repair requirements but it would be interesting to pull out a dynamometer car and compare 6233, 35028, 60163 and when able 2007!!

 

I'm often seeing videos of MN's seemingly outperforming anything other locomotives are doing - perhaps it's an illusion, perhaps I've got rose tinted glasses on ...

 

There's no doubting Tornado's a fantastic iteration of a very good locomotive, and that much thought has gone into the production of a reiteration of the P2 in PoW.

 

Thanks for the informed response.

 

Al.

Edited January 17, 2021 by atom3624

[No Decorum]

41 minutes ago, atom3624 said:

Interesting information indeed.

It's definitely not a competition with highly expensive potential repair requirements but it would be interesting to pull out a dynamometer car and compare 6233, 30528, 60163 and when able 2007!!

 

I'm often seeing videos of MN's seemingly outperforming anything other locomotives are doing - perhaps it's an illusion, perhaps I've got rose tinted glasses on ...

 

There's no doubting Tornado's a fantastic iteration of a very good locomotive, and that much thought has gone into the production of a reiteration of the P2 in PoW.

 

Thanks for the informed response.

 

Al.

I must admit that my eyebrows rose when I learnt that 2007 was going to be based on the original 2001 rather than the version rebuilt to conform to the later P2s. I suggest having a look here – far better than my trying to do a précis.

https://www.p2steam.com/design-study/