Gresley Locotives of the LNER : A1 Class

[neildimmer]

The London and North Eastern Railway LNER Gresley Classes A1 and A3 locomotives represented two distinct stages in the history of the British 4-6-2 "Pacific" steam locomotives designed by Nigel Gresley. They were designed for main line passenger services, initially on the Great Northern Railway (GNR), a constituent company of the London and North Eastern Railway after the amalgamation of 1923, for which they became a standard design. The change in class designation to A3 reflected the fitting to the same chassis of a higher pressure boiler with a greater superheating surface and a small reduction in cylinder diameter, leading to an increase in locomotive weight. Eventually all of the A1 locomotives were rebuilt, most to A3 specifications, but no. 4470 was completely rebuilt as Class A1/1.
The names for the locomotives came from a variety of sources. The first, Great Northern, was named after its parent company. Others were given the names of high-ranking railway officials, but most were given the names of famous racehorses. One was named after the company's most famous long-distance passenger train, the Flying Scotsman.
The new Pacific locomotives were built at the Doncaster "Plant" in 1922 to the design of Nigel Gresley, who had become Chief Mechanical Engineer of the GNR in 1911. The intention was to produce an engine able to handle, without assistance, mainline express services that were reaching the limits of the capacity of the Ivatt large-boilered Atlantics.
Gresley's initial Pacific project of 1915 was for an elongated version of the Ivatt Atlantic design with four cylinders. Finally realising that he was in a design impasse, he took as a model the new American Pennsylvania Railroad class K4 Pacific of 1914. This in turn had been updated from a series of prototypes scientifically developed in 1910 under Francis J. Cole, Alco's Chief Consulting Engineer at Schenectady and the Pennsylvania's K29 Alco prototype of 1911, also designed by Cole. Descriptions of those locomotives appeared in the British technical press at the time and gave Gresley the elements necessary to design a thoroughly up-to-date locomotive.
Design features and construction history
The first two GNR Pacifics, 1470 Great Northern and 1471 Sir Frederick Banbury were introduced in 1922.[1] The Great Northern board ordered a further ten '1470-class' locomotives, which were under construction at Doncaster at the time of the formation of the LNER in 1923.
In line with the philosophy behind Cole's Alco prototypes, the Gresley Pacifics were built to the maximum limits of the LNER loading gauge with a large boiler and wide firebox giving a large grate area. The firebox was set low and rested on the trailing carrying axle. However, unlike the Pennsylvania K4, the firebox was not of the flat-topped Belpaire variety, but a round-topped one that was in line with Great Northern tradition. Features in common with the American types were the downward profile towards the back of the firebox and the boiler tapering towards the front. Heat transfer and the flow of gases were helped by use of a combustion chamber extending forward from the firebox space into the boiler barrel, along with a boiler tube length limited to 19 feet (5.8 m), features inherited from the K4 type but not present on the earlier Cole Prototypes. The boiler pressure was rated at 180 pounds per square inch (1.24 MPa).
The 1470-class Pacific was the third Great Northern locomotive type to incorporate Gresley's universal 3-cylinder layout. All three cylinders drove the middle coupled axle. The outside cranks were set at 120°, with the inside crank displaced by about 7 degrees to allow for the 1:8 inclination of the inside cylinder, this slight deviation from even spacing being a suggestion by Harold Holcroft of the SECR which enabled the outside cylinders to be perfectly horizontal. Gresley conjugated valve gear derived the motion of the inside valve spindle from the two outside valve spindles: this eliminated an inaccessible middle set of valve gear between the frames. A feature of the K4 that had soon been abandoned by the Pennsylvania Railroad was an unusual three-bar version of the Laird slide-bar. However, Gresley adopted this type of slide-bar for all his locomotives and it was later taken up by Bulleid for his Pacifics and by Riddles for the British Railways standard designs.
LNER period
The Great Northern Railway was incorporated into the newly formed LNER as a result of the 1923 Grouping. Gresley was appointed Chief Mechanical Engineer of the new company, which was the second largest of the "Big Four" railway companies in Britain. Realising the need for standardisation, Gresley adopted his GNR Pacific design as the standard express passenger locomotive for the LNER main line, designating it 'A1' within the LNER locomotive classification system. The choice was made after comparative trials with an equivalent North Eastern Railway Pacific, classified 'A2'. Between 1923 and 1925, 51 A1 locomotives were built; twenty by the North British Locomotive Company, and the remainder by Doncaster Works. However, Gresley's Pacifics had been designed to work within the bounds of the Great Northern Railway, meaning maximum distances of less than 200 miles (322 km). After the grouping, the locomotives were required to have a far greater operating range.
Early improvements
In 1924, number 4472 Flying Scotsman, renumbered and named for the occasion, was displayed at the British Empire Exhibition at Wembley along with the first member of the Great Western Railway (GWR) Castle Class, number 4073 Caerphilly Castle. The latter weighed 19.6 long tons (19.9 t; 22.0 short tons) less than the Pacific, but was claimed to be the most powerful locomotive in Britain with a tractive effort rated at 31,825 lbf (141.56 kN).
In the following months, the two railway companies ran comparative exchange trials between the two types from which the Great Western emerged triumphant with 4079 Pendennis Castle. The LNER learned valuable lessons from the trials which resulted in a series of modifications carried out from 1926 on number 4477 Gay Crusader. Changes to the valve gear included increased lap and longer travel, in accordance with Great Western practice; this allowed fuller exploitation of the expansive properties of steam and reduced back pressure from the exhaust, transforming performance and economy; the economies in coal and water consumption achieved were such that the 180 psi Pacifics could undertake long-distance non-stop runs that had previously been impossible. There followed a complete redesign of the valve gear, which was applied to 2555 Centenary in 1927, with the rest of the class being modified in due course.[14] Locomotives with modified valve gear had a slightly raised running plate over the cylinders in order to give room for the longer combination lever necessary for the longer valve travel. Another modification was made in 1927 when number 4480 Enterprise was fitted with a 220 psi (1.52 MPa) boiler. This was closely followed by two other locomotives which also incorporated variations in the cylinder diameter and superheater size for comparative purposes. This led Gresley to make a radical departure from Churchward practice by increasing the number of large tubes containing superheating elements, hence increasing the superheater surface area in contact with the hot gases, thus raising steam temperature. The presence of the larger superheater could be recognised from the square covers on either side of the smokebox, a feature that the locomotives retained throughout the rest of their existence.
At the 1925 British Empire Exhibition, Flying Scotsman was again exhibited; but this time, the GWR sent Pendennis Castle.


1470 Great Northern


https://railway-photography.smugmug.com ... /i-5rBqbx6


1470(4470)/1471(4471) Gresley A1 (4471 Rebuilt to A3) Built 1922 - Railway-Photography
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railway photographs from the last 100 years


https://railway-photography.smugmug.com ... /i-jbZzH2m


1470(4470)/1471(4471) Gresley A1 (4471 Rebuilt to A3) Built 1922 - Railway-Photography
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railway photographs from the last 100 years
4470 Great Northern


https://railway-photography.smugmug.com ... /i-r9cTsRT


1470(4470)/1471(4471) Gresley A1 (4471 Rebuilt to A3) Built 1922 - Railway-Photography
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railway photographs from the last 100 years
1471 (un-named) with indicator shelter Wood Green with 20 coaches 600 Ton tare 3rd September 1922


https://railway-photography.smugmug.com ... /i-tfrvHV2


1470(4470)/1471(4471) Gresley A1 (4471 Rebuilt to A3) Built 1922 - Railway-Photography
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railway photographs from the last 100 years

4471 now named Sir Frederick Banbury



https://railway-photography.smugmug.com ... -6xJCm4K/A


4471 Sir Frederick Banbury Gresley A1
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railway photographs from the last 100 years

Neil

[neildimmer]

I have added 4 more new photos of 4470 Great Northern



4470 Great Northern Stevenage 1929

https://railway-photography.smugmug.com ... /i-nmmHkKd


1470(4470)/1471(4471) Gresley A1 (4471 Rebuilt to A3) Built 1922 - Railway-Photography
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railway photographs from the last 100 years
4470 Great Northern Kings Cross






https://railway-photography.smugmug.com ... /i-V6cDgB3


1470(4470)/1471(4471) Gresley A1 (4471 Rebuilt to A3) Built 1922 - Railway-Photography
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railway photographs from the last 100 years

4470 Great Northern unknown locations



https://railway-photography.smugmug.com ... /i-fbwq8cP


1470(4470)/1471(4471) Gresley A1 (4471 Rebuilt to A3) Built 1922 - Railway-Photography
railway-photography.smugmug.com
railway photographs from the last 100 years




https://railway-photography.smugmug.com ... /i-n8WDRKq


1470(4470)/1471(4471) Gresley A1 (4471 Rebuilt to A3) Built 1922 - Railway-Photography
railway-photography.smugmug.com
railway photographs from the last 100 years
Neil

[StevieG]

The first image of 4470 Neil ("Stevenage"), is heading south on the Up Fast line and, while near to the site of the present day Stevenage station, would then have been about halfway between Stevenage (the old station) and Langley junction (those are Langley box's Up Distant signals beyond the bridge and the loco is right on the commencement of Langley water trough).

[giner]

Spot on, Stevie. It's one of those "if I had a pound for every hour I spent there . . . " locations.

[neildimmer]

Next Collection of Gresley A1 pacifics features 1478+1480 +4472-4481


1478 (un-named yet) Gresley A1



https://railway-photography.smugmug.com ... /i-88hQxCk


4472-4481 A1+(A1 rebuilt to) A3 built 1923 - Railway-Photography
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railway photographs from the last 100 years
1480 (un-named yet) Gresley A1


https://railway-photography.smugmug.com ... /i-pRqQkjR


4472-4481 A1+(A1 rebuilt to) A3 built 1923 - Railway-Photography
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railway photographs from the last 100 years

4472 Flying Scotsman with the down 'Flying Scotsman' Greenwood October 1932 Gresley A1




https://railway-photography.smugmug.com ... /i-HBb5VMF


4472-4481 A1+(A1 rebuilt to) A3 built 1923 - Railway-Photography
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railway photographs from the last 100 years

4472 Flying Scotsman down semi fast at Belle Isle Gresley A1



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4472-4481 A1+(A1 rebuilt to) A3 built 1923 - Railway-Photography
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railway photographs from the last 100 years
4473 Solario



https://railway-photography.smugmug.com ... /i-XSDGTW2


4472-4481 A1+(A1 rebuilt to) A3 built 1923 - Railway-Photography
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railway photographs from the last 100 years


4474 Victor Wild



https://railway-photography.smugmug.com ... /i-cZd8gJh


4472-4481 A1+(A1 rebuilt to) A3 built 1923 - Railway-Photography
railway-photography.smugmug.com
railway photographs from the last 100 years

https://railway-photography.smugmug.com ... /i-ctRchfj


4472-4481 A1+(A1 rebuilt to) A3 built 1923 - Railway-Photography
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railway photographs from the last 100 years

4475 Flying Fox


https://railway-photography.smugmug.com ... /i-m6hV4pm


4472-4481 A1+(A1 rebuilt to) A3 built 1923 - Railway-Photography
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railway photographs from the last 100 years

4478 Hermit


https://railway-photography.smugmug.com ... /i-nRcbvQV


4472-4481 A1+(A1 rebuilt to) A3 built 1923 - Railway-Photography
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railway photographs from the last 100 years
4481 St. Simon Gresley A1


https://railway-photography.smugmug.com ... /i-kqHgVBM


4472-4481 A1+(A1 rebuilt to) A3 built 1923 - Railway-Photography
railway-photography.smugmug.com
railway photographs from the last 100 years

Neil

[neildimmer]

next collection of Gresley A1 pacifics features 2543-2554 built 1924



2547 Doncaster at Doncaster



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2543-2554 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years
2546 Donovan


https://railway-photography.smugmug.com ... /i-mFfVnZM


2543-2554 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years


https://railway-photography.smugmug.com ... /i-DBvLm7M


2543-2554 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years
2551 Woolmer Green c1925 (later named Palatine)


https://railway-photography.smugmug.com ... /i-vPjbGdq


2543-2554 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years

2552 Sansovino



https://railway-photography.smugmug.com ... /i-jx4x3zb


2543-2554 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years


https://railway-photography.smugmug.com ... /i-RvpBXQL


2543-2554 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years
2553 Prince of Wales



https://railway-photography.smugmug.com ... /i-X8M54bf


railway photographs from the last 100 years



https://railway-photography.smugmug.com ... /i-s8qMdhh


2543-2554 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
railway-photography.smugmug.com
railway photographs from the last 100 years


Neil

[neildimmer]

next collection of Gresley A1 pacifics features 2563-2582 built 1924

including this line up

2563 William Whitelaw later renamed Tagalie (second from right) alongside 2596 + 2573 + 2402


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2563 Tagalie (second from right) alongside 2596 + 2573 + 2402
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railway photographs from the last 100 years
2563 William Whitelaw later renamed Tagalie



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2563 William Whitelaw later renamed Tagalie
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railway photographs from the last 100 years
2564 Knight of Thistle Gresley A1

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2563-2582 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years
2566 Ladas Eastfield Shed c1938 Gresley A1



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2563-2582 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years

2569 Haymarket shed c1927 (later named Gladiateur)

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2563-2582 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years


2569 Gladiateur near Reston



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2563-2582 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years

2573 near Reston (later named Harvester)


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2563-2582 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years

2576 The White Knight Edinburgh March 1933 Gresley A1


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2563-2582 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years
2579 Dick Turpin Heaton shed August 1933 Gresley A1


https://railway-photography.smugmug.com ... /i-fHG3qQV


2563-2582 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
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railway photographs from the last 100 years

2581 Neil Gow Stevenage c1933 with the 'Flying Scotsman'


https://railway-photography.smugmug.com ... /i-Jnfr3DR


2563-2582 A1+(A1 rebuilt to) A3 built 1924 - Railway-Photography
railway-photography.smugmug.com
railway photographs from the last 100 years
Neil