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rockershovel

Connection between PRR Atlantics and U.K.?

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Posted (edited)

It’s commonly believed that Gresley was strongly influenced by the Pennsylvania RR’s K4 Pacifics; but what of the earlier Atlantics? Were the GNR Atlantics influenced by the PRR’s success with this type? 

 

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Edited by rockershovel

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W Worsdell visited the Pennsy in 1902 shortly before turning out the NER class V atlantics in 1903 (in fact both he and his brother had worked at Altoona for half a dozen years near the start  of their careers, so I imagine he had plenty of contacts there), and it is known that he was rather impressed with them and they, plus the Ivatt GN locos, were what led him down the atlantic route.

However, the earlier pennsy atlantics were a lot smaller than the E6s

 

e5082.JPG

 

One (no. 7002) survives, although rebuilt with piston valves.

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I think Gresley saw the K4’s and discovered the power they could put out from a 4-6-2.  US railroads were starting to build larger locomotives, not only in size but wheel arrangement which obviously wouldn’t work here in the UK.

 

I think the punch they pulled impressed Gresley a lot.

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On 04/08/2020 at 23:00, jools1959 said:

I think Gresley saw the K4’s and discovered the power they could put out from a 4-6-2.  US railroads were starting to build larger locomotives, not only in size but wheel arrangement which obviously wouldn’t work here in the UK.

 

I think the punch they pulled impressed Gresley a lot.

I don't think Gresley ever visited the USA but it is well known that the LNER obtained a set of K4 drawings which led to the original GNR pacific drawings being radically redesigned.

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The Union Pacific must be the only railway in the world to have copied the Gresley conjugated valve gear! 

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6 hours ago, The Stationmaster said:

I don't think Gresley ever visited the USA .. 


 But he did visit Canada in 1929, and rode on the footplate of at least one Canadian Pacific Selkirk 2-10-4 on the climb from Beavermouth up to Rogers Pass.

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21 hours ago, rockershovel said:

The Union Pacific must be the only railway in the world to have copied the Gresley conjugated valve gear! 

I'm not entirely sure if it was the 'pure' Gresley version or a modification or even the Holcroft version.  But they definitely used what in photios looks very much like Gresley valve gear.  A Wiki source (sorry) states that it was used by Alco under licence for the UP 4-12-2s - but that is a Wiki source so comes with the usual health warning..

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I’m not sure that the Gresley A1 was influenced directly by the Pennsy K4; there are very fundamental differences between them, not least the number of cylinders and Gresley valve gear.  There are certainly similarities as well, driving wheel diameter for one.  I’m sure Gresley must have been fully aware of the K4s, which had been in successful service for 8 years when 1470 came out, but I would stop short of describing a Gresley A1 as a development, or as based in any way on, or inspired by, an American main line loco built for much heavier rail and axle loads.   

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30 minutes ago, The Johnster said:

I’m not sure that the Gresley A1 was influenced directly by the Pennsy K4; there are very fundamental differences between them, not least the number of cylinders and Gresley valve gear.  There are certainly similarities as well, driving wheel diameter for one.  I’m sure Gresley must have been fully aware of the K4s, which had been in successful service for 8 years when 1470 came out, but I would stop short of describing a Gresley A1 as a development, or as based in any way on, or inspired by, an American main line loco built for much heavier rail and axle loads.   

 

The similarity to me seems to be that both were  4-6-2 locomotives, producing similar power ratios per sq ft of grate, at 200psi boiler pressures, similar power to weight ratios and similar driving wheel sizes. Both had the distinctive tapered boiler profile. I haven’t checked the figures but I strongly suspect that the two designs have similar cylinder volumes and piston areas, relative to boiler capacity with the British locomotive favouring three cylinders to suit the smaller British loading gauge and higher running speeds. Loading gauge and fuel probably account for the British locomotive not using the Belpaire firebox, which was well known in the U.K. 

 

Is the A3 a copy of the K4? Clearly not, but I do think there are obvious parallels. Don’t forget that the A3 was not an original design, but a development of an existing design. 

 

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Which is why I discussed the original Gresley GNR A1 design, but you are right, overall cylinder capacity was similar.  The K4 has more grate surface and heating area in a bigger boiler of course.  The K4s were apparently reckoned to be good for 80mph with full loads in daily service, and I’d say that the A1s, certainly the A3s, were capable of 10mph more than that. 
 

Apart from driving wheel size, a more interesting comparison might be between the K4 and a Britannia!

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On 06/08/2020 at 13:44, The Stationmaster said:

I don't think Gresley ever visited the USA but it is well known that the LNER obtained a set of K4 drawings which led to the original GNR pacific drawings being radically redesigned.


I never said that Gresley ever visited the US, I should have said that when Gresley saw the plans, he was very impressed by the output of a PRR K4’s

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Posted (edited)
3 hours ago, The Johnster said:

Which is why I discussed the original Gresley GNR A1 design, but you are right, overall cylinder capacity was similar.  The K4 has more grate surface and heating area in a bigger boiler of course.  The K4s were apparently reckoned to be good for 80mph with full loads in daily service, and I’d say that the A1s, certainly the A3s, were capable of 10mph more than that. 
 

Apart from driving wheel size, a more interesting comparison might be between the K4 and a Britannia!

 

I’m not so sure about that. The E6, K4, A3 and C1 were the peaks of certain trends of Edwardian and WW1 era locomotive design, on their respective sides of the Atlantic. They led long and successful careers, up to the end of steam in some cases. 

 

The Britannia was a next-generation design, and should be compared to the last-generation US monsters which had long since, passed beyond the realms of hand-firing (the 15 short ton, 13.3 long ton capacity tender of the K4 must surely have represented the limits of the possible, in that respect). 

 

 

This leads us to another question, the Standard 2-8-2 neverwazzer. The LNER 2-8-2 design had demonstrated that it was capable of handling trains beyond the capacity of the network to accommodate them. LMS and LNER locomotives were regularly handling the heaviest, fastest trains with 9-10 ton capacity tenders. This was all achieved with grate sizes in the 41-45 sq ft range. The 9F included this feature, with maximum adhesive weight within the design. 

 

 

 

 

Edited by rockershovel

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On 06/08/2020 at 15:00, rockershovel said:

The Union Pacific must be the only railway in the world to have copied the Gresley conjugated valve gear! 

New South Wales D57 class and VR S class in Australia also

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5 minutes ago, MPR said:

New South Wales D57 class and VR S class in Australia also

 

Well THOSE are imposing brutes! Australian locomotives are little known here in the Old Country... love the Commodore Vanderbilt streamliner!

 

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3 hours ago, rockershovel said:

 

I’m not so sure about that. The E6, K4, A3 and C1 were the peaks of certain trends of Edwardian and WW1 era locomotive design, on their respective sides of the Atlantic. They led long and successful careers, up to the end of steam in some cases. 

 

The Britannia was a next-generation design, and should be compared to the last-generation US monsters which had long since, passed beyond the realms of hand-firing (the 15 short ton, 13.3 long ton capacity tender of the K4 must surely have represented the limits of the possible, in that respect). 

 

 

This leads us to another question, the Standard 2-8-2 neverwazzer. The LNER 2-8-2 design had demonstrated that it was capable of handling trains beyond the capacity of the network to accommodate them. LMS and LNER locomotives were regularly handling the heaviest, fastest trains with 9-10 ton capacity tenders. This was all achieved with grate sizes in the 41-45 sq ft range. The 9F included this feature, with maximum adhesive weight within the design. 

 

 

 

 

I suggested the Brit as a comparable loco to the K4 as it was a two cylinder pacific capable of running at about 80mph with a full load, but again you are right of course that it was a creature of a later age, born of austerity and the need for easy preparation and disposal.

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The PRR K4 had a cast steel frame, which the British designs never had. Self-cleaning smokeboxes and rocking grates were common in the US in the inter-War period; shortages of skilled labour, or (quite often) any sort of labour, were a common factor all through American engineering development. 

 

US railroads abandoned the Belpaire firebox because of their trend towards welded construction, which again was a labour saving technique adopted long before the British caught up with it. 

 

 

My meaning was that the Britannia was a last-generation steam locomotive, incorporating the latest thinking of an industry trapped in the time-warp of its mid-nineteenth-Century loading gauge and permanent way. Beyer-Peacock and North British were openly admitting that they could no longer compete, importing cast loco beds from the US for their locos destined for South Africa. 

 

American designers had shown the advantages of diesel traction by 1941; American, German and Swiss networks were running high-capacity main-line services using electric traction by the same time. 

 

But the pre-War designers had shown that it was possible to build locomotives by 1930s methods, which exceeded the capacity of the network. The Britannia and 9F, the mixed-traffic 4-6-0 and urban 2-6-4T types were exactly what British conditions required, and British industry was equipped to construct; but they led to the demise of British locomotive building, and the botched double transition to diesel, and subsequently electric traction. 

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13 minutes ago, rockershovel said:

importing cast loco beds from the US for their locos destined for South Africa.

General Steel Castings in granite city, illinois was a joint venture between alco and baldwin, set up to produce cast loco frames with everything on, cylinders, pilots, the lot.

It wasn't just Beyer, Peacock, they pretty much made all the cast steel loco frames for the entire world.

But the sort of specialisation and investment required to make 90' precision steel castings meant that there probably wasnt enough business for a competitor - hence it being a joint project between alco and baldwin, both vast enterprises with lots of orders and capital to do it. Also, whilst a cast steel loco bed has much better alignment and strength, you probably dont see the benefit of that until locos reach a certain size and power, which was routine in the US, required in some of the colonies, but our loading gauge and antiquated wagons/operating practises meant it wasnt required here.

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There’s a thread elsewhere on RMWeb about the advantages of plate frame construction for British p/way and operating conditions. 

 

It’s also worth reflecting that Baldwin completely failed to transition from the steam age, as did Beyer Peacock and North British...

 

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15 hours ago, rockershovel said:

...This leads us to another question, the Standard 2-8-2 neverwazzer. The LNER 2-8-2 design had demonstrated that it was capable of handling trains beyond the capacity of the network to accommodate them...

This was Derby Beyer-Garratt class thinking all over again. A 2,000hp loco with a branchline axle load is a nonsense, there were plentiful 8F rating eight coupled types of low axleload available to work on branchlines. Build 300 6' wheel 2-8-2s with 22T axleload for the same money as 50 Brits and 250 9F's, and there's a machine for the mainline which would have delivered the best of both designs in a single package. No difficulty with 90mph service speeds, long achieved on 6' wheel UK locos, and plentiful adhesion: equally deals with severe gradients in fast service, and slow speed when slogging on freight.

 

It's not as if there were no exemplars to look at: Riddles team cannot have failed to notice the success of the 141R in France, locos which would pretty much see out steam traction there. And on the LNER Unsteady Eddie had fully demonstrated how to degrade tractive performance by converting 2-8-2s to pacifics, with consequent loss of adhesion.

 

The evidence was available if Riddles et al chose to examine it,  greatest missed opportunity in BR's standards programme.

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