LNER Gresley Classes A1 and A3
Encyclopedia
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- Disambiguation: LNER Class A1LNER Class A1Class A1 in the London and North Eastern Railway's classification system may refer to any of the following British steam locomotives :* The GNR Class A1 or "Gresley A1", a class of 52 Pacific locomotives designed by Sir Nigel Gresley, including the famous Flying Scotsman * The LNER Thompson Class...
, LNER Thompson Class A1/1LNER Thompson Class A1/1The London and North Eastern Railway Thompson Class A1/1 was started in 1945 when a Class A1 went into the works for rebuilding in to the A1/1....
, LNER Peppercorn Class A1LNER Peppercorn Class A1The London and North Eastern Railway Peppercorn Class A1 is a type of express passenger steam locomotive. Forty-nine original Peppercorn Class A1s were built to the design of Arthur Peppercorn during the early British Railways era, but all were scrapped with the discontinuation of steam,...
- Disambiguation: LNER Class A1
The London and North Eastern Railway
London and North Eastern Railway
The London and North Eastern Railway was the second-largest of the "Big Four" railway companies created by the Railways Act 1921 in Britain...
LNER Gresley Classes A1 and A3 locomotives represented two distinct stages in the history of the British 4-6-2
4-6-2
4-6-2, in the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of four leading wheels on two axles , six powered and coupled driving wheels on three axles, and two trailing wheels on one axle .These locomotives are also known as Pacifics...
"Pacific" steam locomotives designed by Nigel Gresley
Nigel Gresley
Sir Herbert Nigel Gresley was one of Britain's most famous steam locomotive engineers, who rose to become Chief Mechanical Engineer of the London and North Eastern Railway . He was the designer of some of the most famous steam locomotives in Britain, including the LNER Class A1 and LNER Class A4...
. They were designed for main line passenger services, initially on the Great Northern Railway
Great Northern Railway (Great Britain)
The Great Northern Railway was a British railway company established by the Great Northern Railway Act of 1846. On 1 January 1923 the company lost its identity as a constituent of the newly formed London and North Eastern Railway....
(GNR), a constituent company of the London and North Eastern Railway after the amalgamation of 1923
Railways Act 1921
The Railways Act 1921, also known as the Grouping Act, was an enactment by the British government of David Lloyd George intended to stem the losses being made by many of the country's 120 railway companies, move the railways away from internal competition, and to retain some of the benefits which...
, 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
Superheater
A superheater is a device used to convert saturated steam or wet steam into dry steam used for power generation or processes. There are three types of superheaters namely: radiant, convection, and separately fired...
surface and a small reduction in cylinder diameter, leading to an increase in locomotive weight. Eventually all of the A1 locomotives were rebuilt to A3 specifications.
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
Flying Scotsman (train)
The Flying Scotsman is an express passenger train service that has been running between London and Edinburgh—the capitals of England and Scotland respectively—since 1862...
(also the name of a racehorse). Flying Scotsman is the sole survivor of the class to be preserved. It is currently under mechanical overhaul at the National Railway Museum
National Railway Museum
The National Railway Museum is a museum in York forming part of the British National Museum of Science and Industry and telling the story of rail transport in Britain and its impact on society. It has won many awards, including the European Museum of the Year Award in 2001...
.
Class A1: Great Northern genesis
The new Pacific locomotives were built at the Doncaster "Plant"Doncaster Works
Doncaster railway works is in the town of Doncaster, South Yorkshire, England.Always referred to as "the Plant", it was established by the Great Northern Railway in 1853, replacing the previous works in Boston and Peterborough...
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 Atlantic
GNR Class C1
The Great Northern Railway Class C1 is a type of 4-4-2 steam locomotive. One, ex GNR 251, later LNER 2800, survives in preservation.- Development :...
s.
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
Pennsylvania Railroad
The Pennsylvania Railroad was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy", the PRR was headquartered in Philadelphia, Pennsylvania....
class K4
PRR K4s
The Pennsylvania Railroad's K4s 4-6-2 "Pacific" was their premier passenger-hauling steam locomotive from 1914 through the end of steam on the PRR in 1957....
Pacific of 1914. This in turn had been updated from a series of prototypes scientifically developed in 1910 under Francis J. Cole, Alco's
American Locomotive Company
The American Locomotive Company, often shortened to ALCO or Alco , was a builder of railroad locomotives in the United States.-Early history:...
Chief Consulting Engineer at Schenectady
Schenectady, New York
Schenectady is a city in Schenectady County, New York, United States, of which it is the county seat. As of the 2010 census, the city had a population of 66,135...
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. 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
Loading gauge
A loading gauge defines the maximum height and width for railway vehicles and their loads to ensure safe passage through bridges, tunnels and other structures...
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
Belpaire firebox
The Belpaire firebox is a type of firebox used on steam locomotives. It was invented by Alfred Belpaire of Belgium. It has a greater surface area at the top of the firebox, improving heat transfer and steam production...
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 pound per square inches (1.24 MPa).
The 1470-class Pacific was the third Great Northern locomotive type to incorporate Gresley’s universal 3-cylinder
Cylinder (steam locomotive)
The cylinders of a steam locomotive are the components that convert the power stored in the steam into motion.Cylinders may be arranged in several different ways.-Early locomotives:...
layout. Drive from all three cylinders was concentrated on the middle coupled axle whilst 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 using Gresley conjugated valve gear
Gresley conjugated valve gear
The Gresley conjugated valve gear is a valve gear for steam locomotives designed by Sir Nigel Gresley, chief mechanical engineer of the LNER, assisted by Harold Holcroft...
to derive the motion of the inside valve spindle from the two outside valve spindles. This was to obviate the need for 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 for all his locomotives and it was also taken up by Bulleid
Oliver Bulleid
Oliver Vaughan Snell Bulleid was a British railway and mechanical engineer best known as the Chief Mechanical Engineer of the Southern Railway between 1937 and the 1948 nationalisation, developing many well-known locomotives.- Early life and Great Northern Railway :He was born in Invercargill,...
for his Pacifics
SR Merchant Navy class
The SR Merchant Navy class , was a class of air-smoothed 4-6-2 Pacific steam locomotives designed for the Southern Railway of the United Kingdom by Oliver Bulleid...
and by Riddles
Robert Riddles
Robert Arthur "Robin" Riddles, CBE, MIMechE, MinstLE was a British locomotive engineer.-LNWR and LMS:Riddles was born in 1892 and entered the Crewe Works of the London and North Western Railway as a premium apprentice in 1909, completing his apprenticeship in 1913...
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 GroupingRailways Act 1921
The Railways Act 1921, also known as the Grouping Act, was an enactment by the British government of David Lloyd George intended to stem the losses being made by many of the country's 120 railway companies, move the railways away from internal competition, and to retain some of the benefits which...
. 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
LNER locomotive numbering and classification
A number of different numbering and classification schemes were used for the locomotives owned by the London and North Eastern Railway and its constituent companies. This page explains the principal systems that were used...
. The choice was made after comparative trials with an equivalent North Eastern Railway
North Eastern Railway (UK)
The North Eastern Railway , was an English railway company. It was incorporated in 1854, when four existing companies were combined, and was absorbed into the London and North Eastern Railway at the Grouping in 1923...
Pacific, classified 'A2
LNER Class A2
The first London and North Eastern Railway Class A2 was a class of 4-6-2 steam locomotive designed by Vincent Raven. Two were built by the North Eastern Railway in 1922 before the grouping and another 3 by the LNER in 1924. Their LNER numbers were 2400-2404...
'. Between 1923 and 1925, 51 A1 locomotives were built; twenty by the North British Locomotive Company
North British Locomotive Company
The North British Locomotive Company was created in 1903 through the merger of three Glasgow locomotive manufacturing companies; Sharp Stewart and Company , Neilson, Reid and Company and Dübs and Company , creating the largest locomotive manufacturing company in Europe.Its main factories were...
, 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 ScotsmanLNER Class A3 4472 Flying Scotsman
The LNER Class A3 Pacific locomotive No. 4472 Flying Scotsman was built in 1923 for the London and North Eastern Railway at Doncaster Works to a design of H.N. Gresley...
, renumbered and named for the occasion, was displayed at the British Empire Exhibition
British Empire Exhibition
The British Empire Exhibition was a colonial exhibition held at Wembley, Middlesex in 1924 and 1925.-History:It was opened by King George V on St George's Day, 23 April 1924. The British Empire contained 58 countries at that time, and only Gambia and Gibraltar did not take part...
at Wembley along with the first member of the Great Western Railway
Great Western Railway
The Great Western Railway was a British railway company that linked London with the south-west and west of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament in 1835 and ran its first trains in 1838...
(GWR) Castle Class
GWR 4073 Class
The GWR 4073 Class or Castle class locomotives are a group of 4-6-0 steam locomotives of the Great Western Railway. They were originally designed by the railway's Chief Mechanical Engineer, Charles Collett, for working the company's express passenger trains.-History:A development of the earlier...
, number 4073 Caerphilly Castle
GWR 4073 Class 4073 Caerphilly Castle
Caerphilly Castle is a member of the GWR 4073 Class built in 1923. Its first shed allocation was Old Oak Common. Its August 1950 shed allocation was Bath Road, Bristol. Its last shed allocation was Cardiff Canton in March 1959...
. The latter weighed 19.6 LT (19.9 t; 22 ST) less than the Pacific, but was claimed to be the most powerful locomotive in Britain with a tractive effort
Tractive effort
As used in mechanical engineering, the term tractive force is the pulling or pushing force exerted by a vehicle on another vehicle or object. The term tractive effort is synonymous with tractive force, and is often used in railway engineering to describe the pulling or pushing capability of a...
rated at 31825 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
GWR 4073 Class 4079 Pendennis Castle
Pendennis Castle is a GWR 4073 Class steam locomotive, preserved at the Didcot Railway Centre.-Operations:The seventh of the first lot of 10 Castles built in 1923/4, No.4079 "Pendennis Castle" was completed at Swindon Works in February 1924...
. 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
Valve gear
The valve gear of a steam engine is the mechanism that operates the inlet and exhaust valves to admit steam into the cylinder and allow exhaust steam to escape, respectively, at the correct points in the cycle...
included increased lap and longer travel, in accordance with Great Western practice; this allowed fuller exploitation of the expansive properties of steam whilst reducing 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. 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 4430 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
Superheater
A superheater is a device used to convert saturated steam or wet steam into dry steam used for power generation or processes. There are three types of superheaters namely: radiant, convection, and separately fired...
size for comparative purposes. This led Gresley to make a radical departure from Churchward
George Jackson Churchward
George Jackson Churchward CBE was Chief Mechanical Engineer of the Great Western Railway in the United Kingdom from 1902 to 1922.-Early career:...
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.
Class A3
The outcome of the various experiments and modifications made to the A1s in the late 1920s was a new Class A3 “Super Pacific”, the first example of which was number 2743 Felstead. This locomotive appeared in August 1928 with 220 psi (1.52 MPa) boiler, 19-inch (483 mm) cylinders, increased superheat, long-travel valves, improved lubrication and modified weight distribution. Another new development was the changeover from right- to left-hand drive, less convenient for a right-handed fireman, but more so for sighting signals, resulting in the modification of all earlier locomotives.Twenty-seven A3s were built from new, until 1935, with little variation except for a new type of boiler with a "banjo dome", an oval steam collector that was placed on top of the rear boiler ring. The first banjo dome was hidden beneath the casing of Cock o’ the North
LNER Class P2
The London and North Eastern Railway Class P2 was a class of 2-8-2 steam locomotives designed by Sir Nigel Gresley for working heavy express trains over the harsh Edinburgh to Aberdeen Line...
of 1934; it was subsequently used in the A4 streamliners
LNER Class A4
The Class A4 is a class of streamlined 4-6-2 steam locomotive, designed by Nigel Gresley for the London and North Eastern Railway in 1935. Their streamlined design gave them high-speed capability as well as making them instantly recognizable, and one of the class, 4468 Mallard, still claims the...
. The last nine A3 Pacifics were constructed with the device in 1935, and it became a standard fitting on all LNER large, wide-firebox boilers that were applied to new locomotives until 1949. It was also applied to replacement boilers on the A3s.
Although all of the original Class A1 locomotives were eventually rebuilt to Class A3 specifications, it was a drawn-out process that lasted until 1949; 60068 Sir Visto was the last locomotive to be converted. The changeover to left-hand drive took longer, and continued into the Fifties.
Further experiments
Despite having settled on a new standard type, Gresley continued to experiment on individual locomotives, in one of which experiments ACFI feedwater heaterFeedwater heater
A feedwater heater is a power plant component used to pre-heat water delivered to a steam generating boiler. Preheating the feedwater reduces the irreversibilities involved in steam generation and therefore improves the thermodynamic efficiency of the system...
s were installed in A1 2576 The White Knight and A3 2580 Shotover. However, on the Pacifics the increase in efficiency was deemed insufficient and the apparatus was eventually removed. In 1935, number 2544 Lemberg received Trofimoff piston valves of an ingenious design with automatically varying steam passages.
A3s 2747 Coronach and 2571 Humorist were subjected to smoke deflection trials following an accident on the London, Midland and Scottish Railway
London, Midland and Scottish Railway
The London Midland and Scottish Railway was a British railway company. It was formed on 1 January 1923 under the Railways Act of 1921, which required the grouping of over 120 separate railway companies into just four...
(LMS) due to poor visibility; this included the modification of the upper smokebox area surrounding the chimney. Originally the whole smokebox wrapper was retained in order to form an air duct, with the exit behind the chimney, but this was found ineffective. The next stage, at least with 2571, was to cut off the top part of the wrapper, but retaining the sloping plate that directed air flow upwards, and therefore lifting the smoke above the locomotive. The original chimney was replaced by a double stove-pipe variety, and miniature deflector plates were added on either side, angled to concentrate the air flow when the locomotive was on the move.
Smoke-lifting devices were not a priority with the normal single-chimney Pacifics. However, with its double chimney and subsequent fitting of a double Kylchap
Kylchap
The Kylchap steam locomotive steam locomotive exhaust system was designed and patented by the famous French steam engineer André Chapelon, using a second-stage nozzle designed by the Finnish engineer Kyösti Kylälä and known as the Kylälä spreader; thus the name KylChap for this design.The Kylchap...
exhaust in 1937, Humorist continued to pose a problem in this regard and always had small wings on either side of the chimney. Finally, in the 1950s, it acquired the Peppercorn
Arthur Peppercorn
Arthur Henry Peppercorn, OBE was the last Chief Mechanical Engineer of the London and North Eastern Railway.- Career :...
-type of deflector plates.
Tenders
The original A1s were coupled to a traditional Great Northern type of tender with coal rails of a design that can be traced back to StirlingPatrick Stirling
Patrick Stirling was Locomotive Superintendent of the Great Northern Railway.His father Robert Stirling was also an engineer. His brother James Stirling was also a locomotive engineer...
days. The A1-variant was a much-enlarged eight-wheel version carrying 8 LT (8.13 t; 8.96 ST) of coal and 5000 gallons (22,730.5 l) of water. In 1928, a new special type of tender body was built for the new non-stop Flying Scotsman train
Flying Scotsman (train)
The Flying Scotsman is an express passenger train service that has been running between London and Edinburgh—the capitals of England and Scotland respectively—since 1862...
. This tender had a corridor connection
Corridor connection
A Corridor connection is a flexible connector fitted to the end of a railway coach to enable passage from one coach to another without falling out of the train.-Coaches:...
and an access tunnel through the water tank. It was of a more modern design with high side sheets curved in at the top and had a coal capacity of 9 LT (9.14 t; 10.08 ST). In order to be able to pack an extra ton of coal, a single coal rail was provided on this particular series, but was later deemed unnecessary. Ten of these corridor tenders were built, and a non-corridor version of similar design followed with 8-ton coal capacity and no coal rail. Further series of both types had disk wheels instead of the previous spoked variety.
Pre-war performance
The early A1 Pacifics were a match for the performances demanded of them in the early 1920s. They were certainly able to take loads single-handed that were beyond the capacity of their Atlantic predecessorsGNR Class C1
The Great Northern Railway Class C1 is a type of 4-4-2 steam locomotive. One, ex GNR 251, later LNER 2800, survives in preservation.- Development :...
as was shown in a test run made by 1471 when it took a 20-coach train weighing 600 LT (609.6 t; 672 ST) over the 105 miles (169 km) from London to Grantham at an average speed of 51.8 miles per hour (83.4 km/h). However this was at the cost of heavy coal consumption, and general performance was well below the ultimate potential of the design. This was largely due to a regression from the earlier 3-cylinder 2-6-0 design, which was the first to have the standard Gresley conjugated motion combined with long valve travel. However, practical problems were experienced with components quickly suffering from premature wear, especially in the main bearing of the large 2:1 lever which had not yet been fitted with the very necessary ball race
Ball bearing
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races.The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit...
; excessive 'play' led to so much over-travel of the middle valve, that it began to hit the end-covers. In order to prevent this, when applying the gear to the Pacifics, Gresley fell back on the expedient of shortening valve travel even though that choked the exhaust at speed, was responsible for the heavy coal consumption, and negated most of the advantages gained by the locomotive's revolutionary design. However, by incorporating the Great Western-inspired valve modifications, the economies in coal and water consumption achieved were such that the 180 psi Pacifics could undertake long-distance non-stop runs that were previously impossible.
The first and most spectacular outcome occurred in 1928, when the Pacifics were called upon daily to work the Flying Scotsman train non-stop over the 392 miles (630.9 km) between London and Edinburgh. Initially three A1s and two A3s took turns on this service. The modifications also gave the A1 locomotives greater speed potential, and the proof of this came in 1933 when a high-speed 3-car diesel railcar service had been mooted. As this would have provided limited accommodation for passengers, it was proposed to use steam traction at similar service speeds with six carriages. A trial return run between London and Leeds was made with modified A1 locomotive number 4472, Flying Scotsman; on the return trip with 6 coaches weighing 208 LT (211.3 t; 233 ST) it attained 100 mph (160.9 km/h) (160 km/h) just outside in Lincolnshire
Lincolnshire
Lincolnshire is a county in the east of England. It borders Norfolk to the south east, Cambridgeshire to the south, Rutland to the south west, Leicestershire and Nottinghamshire to the west, South Yorkshire to the north west, and the East Riding of Yorkshire to the north. It also borders...
for just over 600 yards (549 m). There were earlier claims to this speed, notably by the Great Western locomotive 3440 City of Truro
GWR 3700 Class
The Great Western Railway 3700 Class, or City Class, locomotives were a series of twenty 4-4-0 steam locomotives, designed for hauling express passenger trains.-Construction:...
, but this 1933 run is generally considered to be the first reliably recorded instance. On a later trial run to Newcastle-upon-Tyne and back in 1935, A3 number 2750 Papyrus reached 108 miles per hour (173.8 km/h) hauling 217 LT (220.5 t; 243 ST) at the same spot, maintaining a speed above 100 mph (161 km/h) for 12.5 consecutive miles (20.1 km), the world record for a non-streamlined locomotive, shared with a French Chapelon Pacific.
Wartime service
Along with all the Gresley 3-cylinder types, the Pacifics suffered from low wartime maintenance standards, conditions for which they had not been designed. Gresley’s sudden death in 1941 and an unsympathetic successor, Edward ThompsonEdward Thompson (engineer)
Edward Thompson was Chief Mechanical Engineer of the London and North Eastern Railway between 1941 and 1946.- Biography :Edward Thompson was the son of an assistant master at Marlborough College. He was educated at Marlborough before taking the Mechanical Science Tripos at Pembroke College,...
, did not help matters in this respect. In 1945 Thompson took the opportunity to rebuild the first of Gresley's A1 Pacifics, Great Northern, to the LNER Class A1/1
LNER Thompson Class A1/1
The London and North Eastern Railway Thompson Class A1/1 was started in 1945 when a Class A1 went into the works for rebuilding in to the A1/1....
specification with divided drive and separate valve gear to the inside cylinder. The A1/1 was classified in this manner after Arthur Peppercorn
Arthur Peppercorn
Arthur Henry Peppercorn, OBE was the last Chief Mechanical Engineer of the London and North Eastern Railway.- Career :...
had designed and constructed his own Class A1s
LNER Peppercorn Class A1
The London and North Eastern Railway Peppercorn Class A1 is a type of express passenger steam locomotive. Forty-nine original Peppercorn Class A1s were built to the design of Arthur Peppercorn during the early British Railways era, but all were scrapped with the discontinuation of steam,...
in 1947. Thompson intended to rebuild to this configuration all the Gresley A1s that had not been converted to A3 standard, but this never happened.
Post-war recovery and nationalisation
Thompson's successor, Peppercorn, reverted to Gresley's design principles. However as far as the Pacifics were concerned, one Thompson feature that Peppercorn did retain was the divided drive, where the inside cylinder was set well forward driving the front axle, whilst the two outside cylinders reverted to the A1 and A3 location driving the middle one. Gresley had always strongly opposed divided drive; moreover his Pacifics had always been appreciated for their easy riding, a reputation not shared by those of his successors and a possible contributing factor towards the continued strong presence of Gresley Pacifics on the East Coast Main LineEast Coast Main Line
The East Coast Main Line is a long electrified high-speed railway link between London, Peterborough, Doncaster, Wakefield, Leeds, York, Darlington, Newcastle and Edinburgh...
right down to the end of steam traction in the early 1960s.
The Gresley 3-cylinder drive arrangement continued to bring a number of practical problems, the root of which was probably the need for the inside cylinder to be steeply inclined in order to give space for the inside connecting rod to clear the leading coupled axle; at the same time, the inside valve spindle had to be parallel with the outside ones from which it derived its motion. This problem had been overcome by what Holcroft called a "twist in the ports" (the passages that carried steam in and out of the cylinders). It also meant that the length of these passages was greater than that generally recommended, increasing "dead space", and this was combined with a shorter exhaust passage. The net result would be rather different working conditions in the middle cylinder from those on the outside. A contributing problem was also that any elongation of the outside valve spindles was multiplied by the conjugated valve gear. Although this had been anticipated at the design stage, the overall consequence was that the inside cylinder had a tendency to give more power than the other two as speed increased leading to the overloading of the inside connecting rod bearings, especially the big-end which was liable to overheat and fail. Various experiments were tried over the years to cure this chronic ailment, and it was only towards the end of the steam era that a real solution was found in the Great Western type of big-end bearing. Other problems persisted, such as a stiff, insensitive regulator and overall design flaws that hampered maintenance.
In spite of all this and the introduction of more recent Pacifics, by the middle of the 1950s Gresley types were continuing to have the quasi-monopoly of East Coast Main Line express passenger services, and as the Sixties approached they went through yet another series of improvements comparable to those of the 1920s. The most significant of these was the fitting of the French double Kylchap
Kylchap
The Kylchap steam locomotive steam locomotive exhaust system was designed and patented by the famous French steam engineer André Chapelon, using a second-stage nozzle designed by the Finnish engineer Kyösti Kylälä and known as the Kylälä spreader; thus the name KylChap for this design.The Kylchap...
exhaust system, which was entirely due to the persistence from 1956 of P. N. Townend, Assistant District Motive Power Superintendent at King's Cross locomotive shed. These modifications not only drastically reduced exhaust back pressure, making the locomotives far more economical and free-running, but kept the firetubes clean, greatly reducing turn-around time, so much so that they were able to fit into the more intensive diesel locomotive workings. The Kylchap arrangement was already being universally applied to the A4 streamlined Pacifics
LNER Class A4
The Class A4 is a class of streamlined 4-6-2 steam locomotive, designed by Nigel Gresley for the London and North Eastern Railway in 1935. Their streamlined design gave them high-speed capability as well as making them instantly recognizable, and one of the class, 4468 Mallard, still claims the...
, though with the non-streamlined A3 locomotives, the soft exhaust gave rise to smoke drift obscuring the driver’s forward vision. The solution came in the form of narrow German-style smoke deflectors
Smoke deflectors
Smoke deflectors are vertical plates attached to the front of a steam locomotive on each side of the smokebox. They are designed to lift smoke away from the locomotive at speed so that the driver has better visibility unimpaired by drifting smoke....
, which somewhat changed the appearance of the A3 locomotives in their latter days.
The prototype locomotive, number 60113 Great Northern, had been rebuilt by Edward Thompson into a virtually new design. The first to be withdrawn was 60104 Solario in 1959, followed by 60095 Flamingo and 60055 Woolwinder in 1961. Otherwise, the class remained intact until 1962, and was still operating on express passenger work. The last class member to be withdrawn by British Railways was number 60052, Prince Palatine in January 1966.
Preservation
The sole surviving member of the A3s and A1s is 4472 (60103) Flying ScotsmanLNER Class A3 4472 Flying Scotsman
The LNER Class A3 Pacific locomotive No. 4472 Flying Scotsman was built in 1923 for the London and North Eastern Railway at Doncaster Works to a design of H.N. Gresley...
. The locomotive was withdrawn from service with British Rail
British Rail
British Railways , which from 1965 traded as British Rail, was the operator of most of the rail transport in Great Britain between 1948 and 1997. It was formed from the nationalisation of the "Big Four" British railway companies and lasted until the gradual privatisation of British Rail, in stages...
ways in 1963 and was sold for preservation to Alan Pegler
Alan Pegler
Alan Francis Pegler OBE FRSA is a British railway preservationist, best known for saving LNER Class A3 4472 Flying Scotsman and his involvement with the Ffestiniog Railway. He was awarded an OBE in the 2006 New Years Honours list. He is a Member of Jesus College, Cambridge, 1938.-Notes:...
. After overhaul, Scotsman worked a number of railtours, including a non-stop London–Edinburgh run in 1968, the final year of steam traction on British Railways. After a much-publicised appeal in 2004, Scotsman was purchased by the National Railway Museum
National Railway Museum
The National Railway Museum is a museum in York forming part of the British National Museum of Science and Industry and telling the story of rail transport in Britain and its impact on society. It has won many awards, including the European Museum of the Year Award in 2001...
in York
York
York is a walled city, situated at the confluence of the Rivers Ouse and Foss in North Yorkshire, England. The city has a rich heritage and has provided the backdrop to major political events throughout much of its two millennia of existence...
and is now part of the National Collection. , the locomotive is undergoing a major rebuild at the museum and is due to resume running in September 2011.
In fiction
In The Railway SeriesThe Railway Series
The Railway Series is a set of story books about a railway system located on the fictional Island of Sodor. There are 42 books in the series, the first being published in 1945. Twenty-six were written by the Rev. W. Awdry, up to 1972. A further 16 were written by his son, Christopher Awdry; 14...
children's books by the Rev. W. Awdry, the character Gordon the Big Engine
Gordon the Big Engine
Gordon the Big Engine is a fictional anthropomorphic tender locomotive in The Railway Series books by Rev. W. Awdry. Gordon is painted blue and carries the number 4. Gordon views himself as the most important engine because he is the biggest and he pulls the Express...
is loosely based on an A1. According to the Rev. Awdry, in The Island of Sodor: Its People, History and Railways, Gordon was a "hush-hush" experimental prototype for Gresley's Pacific locomotives for the GNR. Built in 1922, Gordon was sold to the Fat Controller
The Fat Controller
The Fat Controller is the head of the railway in The Railway Series of books written by the Rev. W. V. Awdry. In the first two books in the series he is known as The Fat Director...
in 1923, once testing was complete. Following problems with the conjugated valve gear, Gordon was substantially rebuilt in 1939 on a two-cylinder chassis designed by the Fat Controller (which explains why Gordon did not look exactly like an A1 in the books).
Flying Scotsman also appears in The Railway Series in the book, Enterprising Engines.
Models
Tri-angTri-ang Railways
Tri-ang Railways was a British manufacturer of toy trains, one of the elements of the Lines Bros Ltd company who traded using the Tri-ang brand name...
, and later Hornby
Hornby Railways
Hornby Railways is the leading brand of model railway in the United Kingdom. Its roots date back to 1901, when founder Frank Hornby received a patent for his Meccano construction toy. The first clockwork train was produced in 1920. In 1938, Hornby launched its first 00 gauge train...
, have produced 'OO'-scale models of Flying Scotsman almost continuously since the 1960s. In the 2000s, Hornby also produced live steam
Live steam
Live steam is steam under pressure, obtained by heating water in a boiler. The steam is used to operate stationary or moving equipment.A live steam machine or device is one powered by steam, but the term is usually reserved for those that are replicas, scale models, toys, or otherwise used for...
examples, re-using the chassis from the initial LNER Class A4
LNER Class A4
The Class A4 is a class of streamlined 4-6-2 steam locomotive, designed by Nigel Gresley for the London and North Eastern Railway in 1935. Their streamlined design gave them high-speed capability as well as making them instantly recognizable, and one of the class, 4468 Mallard, still claims the...
models. Other manufacturers have produced models in other scales, such as Minitrix (N-gauge) and Bassett-Lowke (O-gauge).