The LNER Class A4 is a class of streamlined 4-6-2steam 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 recognisable, and one of the class, 4468 Mallard, holds the record as the world's fastest steam locomotive. Thirty-five of the class were built to haul express passenger trains on the East Coast Main Line route from London Kings Cross via York to Newcastle, and later via Newcastle to Edinburgh, Scotland. They remained in service on the East Coast Main Line until the early 1960s when they were replaced by Deltic diesel locomotives; they themselves proving to be worthy successors to the A4s.[2] Several A4s saw out their remaining days until 1966 in Scotland, particularly on the Aberdeen – Glasgow express trains, for which they were used to improve the timing from 3.5 to 3 hours.
During a visit to Germany in 1933, Gresley had been inspired by high-speed streamlined Flying Hamburger diesel trains. The London and North Eastern Railway (LNER) had considered purchasing similar trains for use from London to Newcastle but the diesel units of the time did not have sufficient passenger carrying capacity and the capital investment in the new technology was prohibitive.
Gresley was sure that steam could do equally well with a decent fare-paying load behind the locomotive. Following trials in 1935 in which one of his A3 Pacifics, No. 2750 Papyrus, recorded a new maximum of 108mph (173.8km/h) and completed the journey in under four hours, the LNER's Chief General Manager Ralph Wedgwood authorised Gresley to produce a streamlined development of the A3.[3] Initially four locomotives were built, all with the word 'silver' in their names. The first was 2509 Silver Link, followed by 2510 Quicksilver, 2511 Silver King and 2512 Silver Fox. During a press run to publicise the service, Silver Link twice achieved a speed of 112.5mph (181.1km/h), breaking the British speed record and sustained an average of 100mph (160.9km/h), over a distance of 43 miles (69.2km).[4]
Following the commercial success of the Silver Jubilee train, other streamlined services were introduced: The Coronation (London-Edinburgh, July 1937) and the West Riding Limited (Bradford & Leeds-London & return, November 1937) for which more A4s were built.
Design
The A4 Pacifics were designed for high-speed passenger services. The application of internal streamlining to the steam circuit, higher boiler pressure and the extension of the firebox to form a combustion chamber all contributed to a more efficient locomotive than the A3; consumption of coal and water were reduced. A further design improvement was fitting a Kylchap double-chimney, first on 4468 Mallard in March 1938. The double-chimney improved the capability of the locomotives further, and the last three locomotives of the class (4901 Capercaillie, 4902 Seagull and 4903 Peregrine) were fitted with the Kylchap exhaust from new and the rest of the class acquired it in the late 1950s.
An unidentified A4, showing their original appearance with streamlined skirts covering the wheels.
The class was noted for its streamlined design, which not only improved its aerodynamics, increasing its speed capabilities, but also created an updraught to lift smoke away from the driver's line of vision, a problem inherent in many steam locomotives particularly those operated with short cut off valve events; fitting smoke deflectors was an alternative solution.[5]:56 The distinctive design made it a particularly attractive subject for artists, photographers and film-makers. The A4 Class locomotives were known by trainspotters as "streaks".
The streamlining side skirts (valances) designed by Oliver Bulleid to aerofoil shape that were fitted to all the A4 locomotives, were removed during the Second World War to improve access to the valve gear for maintenance and were not replaced.[6] This apart, the A4 was one of few streamlined steam locomotive designs in the world to retain its casing throughout its existence. Many similar designs, including the contemporary Coronation Class, had their streamlining removed or cancelled to cut costs, simplify maintenance and increase driver visibility.
World record
Plaque on Mallard in commemoration of breaking the previous world speed record of 124.5 mph
On 3 July 1938, 4468 Mallard - the first of the class to enter service with the Kylchap exhaust - pulling six coaches and a dynamometer car, set a world speed record (indicated by the dynamometer) of 126mph (202.8km/h). Gresley never accepted it as the record-breaking maximum. He claimed this speed could only have been attained over a few yards, though he was comfortable that the German speed record of 124.5mph (200.4km/h) had been surpassed.[7] Close analysis of the dynamometer roll (currently at the NRM) of the record run confirms that Mallard's speed did in fact exceed that of the German BR05002.[8]:64 The Mallard record reached its maximum speed on a downhill run and failed technically in due course, whereas 05002's journey was on level grade and the engine did not yet seem to be at its limit.[9] On the other hand, the German train was four coaches long (197 tons), but Mallard's train had seven coaches (240 tons).[9] One fact, often ignored when considering rival claims, is that Gresley and the LNER had just one serious attempt at the record, which was far from a perfect run with a 15mph permanent way check just north of Grantham; despite this a record was set.[10]:125 Gresley planned another attempt in September 1939, but was prevented by the outbreak of World War II.[10]:126 Prior to the record run on 3 July 1938, it was calculated that 130mph (210km/h) was possible; Driver Duddington and LNER Inspector Sid Jenkins both said they might well have achieved this figure had they not had to slow for the Essendine junctions.[10]:125
At the end of Mallard's record run, the middle big end (part of the motion for the inside cylinder) ran hot (indicated by the bursting of a heat-sensitive "stink bomb" placed in the bearing for warning purposes), the bearing metal had melted and the locomotive had to stop at Peterborough rather than continue to London.[10]:103,126 Deficiencies in the alignment of the Gresley-Holcroft derived motion meant that the inside cylinder of the A4 did more work at high speed than the two outside cylinders – on at least one occasion this led to the middle big end wearing to such an extent that the increased piston travel knocked the ends off the middle cylinder[11] – and this overloading was mostly responsible for the failure.[citation needed]
Performance in service
No other British steam locomotives have a longer or more consistent record of high speed running than the A4s. Instances of 100mph running by them must exceed those of all other types combined,[12] though 90mph running was a relatively rare event with steam traction, much less 100mph. It should also be remembered that A4s operated on the East Coast Main Line which has more opportunities for high speed running (particularly Stoke Bank) than any other in the UK.
George Henry Haygreen (left) on his retirement day with Fireman Charlie Fisher
In August 1936 the Silver Jubilee train on the descent of Stoke Bank headed by 2512 Silver Fox driven by George Henry Haygreen achieved a maximum of 113mph (181.9km/h), then the highest speed attained in Britain with an ordinary passenger train.[13] The fastest recorded post-war speed with British steam was also recorded by an A4. This occurred on 23 May 1959 on the Stephenson Locomotive Society Golden Jubilee special when 60007 Sir Nigel Gresley achieved 112mph when hauling 400 tons down Stoke Bank. The driver, Bill Hoole, had hoped for an attempt to beat Mallard's record but Alan Pegler, who was on the footplate and mindful of the risks, told him to ease off.[8]:90–92
Although A4s were primarily designed for high speed express work they were also capable of high power outputs. In 1940, 4901 Capercaillie exerted 2,200 drawbar horsepower on the straight and level track north of York when hauling 21 coaches (730 tons gross) at an average of 75.9mph for 25 miles.[5]:153 On W. A. Tuplin's method for grading steam locomotive performance based on both power output and duration of effort, this was the highest value ever achieved by any British locomotive, at Grade 26.[14]
The highest recorded power output from an A4 was 2,450 drawbar horsepower when Mallard herself was hauling 11 coaches (390 tons tare, 415 tons gross) up Stoke Bank at a sustained 80mph in 1963.[15]O. S. Nock thought this performance superior to Mallard's world record run in 1938. An A4 with the same load on a "good run" would be doing about 50 to 60mph at the summit of Stoke Bank. On a run on 8 September 1961 Mallard had its train travelling at 78mph.[16]
Although newer Pacifics had been introduced since the war and the streamlined trains were never reinstated, the A4s continued on top link duties, notably on the London to Edinburgh services.
Even after the war was over, the A4s still continued to perform non-stop services. In August 1948, 60028 Walter K. Whigham managed to perform a non-stop service run from King's Cross to Edinburgh, setting the record for distance travelled for 408.65 miles. It would hold this record until 4472 Flying Scotsman's visit to Australia in 1988.[17]
Improved methods of aligning the Gresley conjugated valve gear in the 1950s led to tighter tolerances for the bearings used within it and, consequently, to almost total eradication of the overloading of the middle cylinder.[citation needed] History repeated itself with the inside big end being replaced by one of the Great Western type, after which there was no more trouble, provided that maintenance routines were respected.[18]
The wholesale application of double Kylchap chimneys to the entire class was entirely due to the persistence of P. N. Townend, the Assistant Motive Power Superintendent at King's Cross from 1956. He, at first, met with considerable resistance from higher authority. When permission was eventually given, it was found that the economy obtained over the single chimney A4s was from six to seven pounds of coal per mile, which more than justified the expense of the conversion.[19]
These improvements led to greatly increased availability.
The first four locomotives included the word 'silver' in their names because they were intended to haul the Silver Jubilee train. 2512 Silver Fox of this batch carried a stainless-steel fox near the centre of the streamline casing on each side, made by the Sheffield steelmakers Samuel Fox and Company.[10]:120 The next batch of A4s were named after birds, particularly those that were fast flyers, Gresley being a keen bird-watcher. Five (4488–92) were named after British Empire countries to haul the new Anglo-Scottish Coronation train; and two (4495/6), intended to haul the new West Riding Limited, received names connected to the wool trade: Golden Fleece and Golden Shuttle.[23]
A rare gathering of three ex-LNER A4 locomotives at Grosmont, North Yorkshire Moors Railway, on 4 April 2008, as 60009 Union of South Africa, 60007 Sir Nigel Gresley and 60019 Bittern lined up at 7:30 am in preparation for service.
4498 was the hundredth Gresley Pacific to be built and was named after him. Subsequently, some other A4s were later renamed, usually to names of directors of the LNER.
Withdrawal
One locomotive was withdrawn and scrapped after being damaged beyond repair in a German bombing raid on York on 29 April 1942 during World War II; this was No. 4469 Sir Ralph Wedgwood, which at the time had been overhauled and was based at Gateshead. It was running local trains to run it in and was stabled in York North Shed (now the National Railway Museum) where it suffered a direct hit; however, its tender survived and was later coupled to a Thompson A2/1.
Six of the locomotives have been preserved; three of them were assigned to sheds in Scotland after the closure of King's Cross shed (34A) to steam in 1964.[citation needed] Four A4s are in the UK and have run on the BR main lines at some point during their preservation career. Another two (Dominion of Canada and Dwight D. Eisenhower) were donated to the Canada and the US, respectively, upon withdrawal by British Railways. Both North American-based A4s, along with the other three British-based A4s were moved to the National Railway Museum, York, in late 2012 on three-year loans as part of the NRM's 2013 celebrations of the 75th anniversary of Mallard breaking the world speed record for steam, bringing all six preserved A4s together.[24] During 2013, 4464 'Bittern' underwent a series of high-speed runs, partly in commemoration of Mallard's record, partly to see if mainline speeds for certain heritage steam locomotives could be increased (The current maximum is 75mph.). During the "Tyne Tees Streak" run, Bittern broke its own 91mph speed record set just a few months prior by reaching a maximum speed of 93mph (149.7km/h).
From 2015 to 2020, Union of South Africa was the only A4 operational with a valid mainline certificate until it expired in 2020; 60007 was withdrawn for overhaul on 20 September 2015 and 4464 operated until the end of 2015 at the Watercress Line when it was withdrawn and placed on static display in 2018 at Crewe. Union of South Africa was withdrawn in October 2021 due to boiler issues and with the coming expiration of its boiler certificate in early 2022. Sir Nigel Gresley returned to the mainline on 21 April 2022 and worked its inaugural railtour on 21 May 2022 following the completion of its major overhaul. As of 2023, 5 of 6 surviving A4's are on static display, the only working one being 60007 Sir Nigel Gresley.[25] 60019 is planned to be moved from Margate to North Yorkshire for a mainline standard overhaul in 2024.[26]
Withdrawn from service on 5 October 2021 due to boiler issues and boiler ticket expiry in early 2022.
Due to controversial and political issues in South Africa in the 1980s involving racial apartheid the engine was renamed to Osprey. It returned to its original name in the 1990s.
Originally planned to be named Buzzard, but was changed to Woodcock and then changed to Dominion of Canada.[27][28] The name Woodcock was given to engine No. 4493.
Originally planned to be named Sparrow Hawk but was named Golden Shuttle instead and was eventually renamed to Dwight D Eisenhower. The name Sparrow Hawk was used for engine No. 4463.[29]
Moved to the Severn Valley Railway for test running and appeared at the April Spring Steam Gala.
Worked Inaugural mainline railtour on 21 May 2022.[25]
Models
One of the first two Hornby Dublo locomotive models produced, in 1938, was an A4.[32] In 1999 a 'Super Detail' Hornby A4 was released,[citation needed] later complemented by a budget 'Railroad' model[citation needed]Hornby also produced an 'OO'-scale live steam version in September 2003, that used an electrically heated boiler to produce steam – not previously possible in such a small model. Trix produced an 'OO' scale model A4 from 1970; it was re-branded as a Liliput model in 1974 and survives to this day in modified form as a Bachmann model – Kader, Bachmann's parent company, had bought Liliput in 1993.[33] In September 2004, Hornby unveiled retooled OO gauge models of the A4 in LNER blue, LNER black and BR green.[34]
During the 1980s, Minitrix produced British N gauge models of Mallard, both as 4468 in LNER blue and 60022 in BR green, and 4498 Sir Nigel Gresley in LNER blue. From the 1990s, Graham Farish produced British N gauge models of the A4. In 2012, Dapol introduced a British N gauge model of 60017 Silver Fox in BR green.[35]
Related Research Articles
Sir Herbert Nigel Gresley was a British railway engineer. He was one of Britain's most famous steam locomotive engineers, who rose to become Chief Mechanical Engineer (CME) of the London and North Eastern Railway (LNER). He was the designer of some of the most famous steam locomotives in Britain, including the LNER Class A1 and LNER Class A4 4-6-2 Pacific engines. An A1 Pacific, Flying Scotsman, was the first steam locomotive officially recorded over 100 mph in passenger service, and an A4, number 4468 Mallard, still holds the record for being the fastest steam locomotive in the world (126 mph).
LNER Class A4 4468 Mallard is a 4-6-2 ("Pacific") steam locomotive built in 1938 for operation on the London and North Eastern Railway (LNER) at Doncaster Works to a design of Nigel Gresley. Its streamlined, wind tunnel tested design allowed it to haul long distance express passenger services at high speeds. On 3 July 1938, Mallard broke the world speed record for steam locomotives at 126 mph (203 km/h), which still stands today.
60009 Union of South Africa is a LNER Class A4 steam locomotive built at Doncaster Works on 16 April 1937. It is one of six surviving A4s. Its mainline certification expired in April 2020. As the locomotive is subject to a boiler inspection, it was moved to the East Lancashire Railway as the original plan was to keep it running there until the end of boiler certificate and then send it somewhere else for static display, but a cracked boiler tube forced it into retirement prematurely. It was briefly renamed Osprey during part of the 1980s and 1990s due to political opposition against apartheid in South Africa at the time.
The Silver Jubilee was a named train of the London and North Eastern Railway (LNER) that ran between 1935 and 1939.
No. 4472 Flying Scotsman is a LNER Class A3 4-6-2 "Pacific" steam locomotive built in 1923 for the London and North Eastern Railway (LNER) at Doncaster Works to a design of Nigel Gresley. It was employed on long-distance express passenger trains on the East Coast Main Line by LNER and its successors, British Railways' Eastern and North Eastern Regions, notably on The Flying Scotsman service between London King's Cross and Edinburgh Waverley after which it was named.
The London and North Eastern Railway (LNER) Class V2 2-6-2 steam locomotives were designed by Sir Nigel Gresley for express mixed traffic work, and built at the LNER shops at Doncaster and Darlington between 1936 and 1944. The best known is the first of the class, 4771 Green Arrow, which is the sole survivor of the class.
60008 Dwight D Eisenhower is an LNER Class A4 steam locomotive named after Dwight D. Eisenhower, the United States General of the Army.
4464Bittern is a London and North Eastern Railway (LNER) Class A4 steam locomotive. Built for the LNER and completed on 18 December 1937 at Doncaster Works as works number 1866, it received number 4464. After that it was renumbered 19 on 16 August 1946 under the LNER 1946 renumbering scheme, and finally 60019 by British Railways on 10 October 1948, after nationalisation. Of the 35 strong class, it is one of six to survive into preservation but it is one of only two currently scheduled to be certified for mainline use.
60007 Sir Nigel Gresley is an LNER Class A4 4-6-2 ("Pacific") steam locomotive built at Doncaster Works in 1937 to a design of Sir Nigel Gresley for operation on the London and North Eastern Railway (LNER). The locomotive holds the post-war speed record for steam locomotives on British Railways. The locomotive was withdrawn from service in 1966 and purchased for preservation the same year; it is one of six A4s to be preserved.
4489 Dominion of Canada is an LNER Class A4 steam locomotive. It is a 4-6-2 locomotive built to the same design by Sir Nigel Gresley as the more famous Mallard. There were 35 A4 locomotives built in total. Originally numbered 4489, it was renumbered 10 on 10 May 1946, under the LNER 1946 renumbering scheme of Edward Thompson and, after nationalisation in 1948, British Railways added 60000 to its number so it became 60010 on 27 October 1948. It was renumbered back to 4489 following a cosmetic restoration at the National Railway Museum in York during late 2012 and early 2013.
The London and North Eastern Railway 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 and later express 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.
LNER Class A4 2509 Silver Link was a 4-6-2 "Pacific" built in 1935 for the London and North Eastern Railway. It was the first of the Streamlined Class A4s built to haul express passenger trains on the East Coast Main Line (ECML). No. 2509 was one of the four A4s to be painted in a special two-tone grey livery to pull a new train called the Silver Jubilee.
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. It enables a three-cylinder locomotive to operate with only the two sets of valve gear for the outside cylinders, and derives the valve motion for the inside cylinder from them by means of levers. The gear is sometimes known as the Gresley-Holcroft gear, acknowledging Holcroft's major contributions to its development.
The LMS Coronation Class No. 6220Coronation was a British steam locomotive.
The London and North Eastern Railway (LNER) Class B17, also known as "Sandringham" or "Footballer" class was a class of 4-6-0 steam locomotive designed by Nigel Gresley for hauling passenger services on the Great Eastern Main Line. In total 73 were built.
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. As they were to serve on Scottish expresses, they were given famous names from Scottish lore.
LNER Class A4 4902 Seagull was one of 35 Doncaster built LNER Class A4 Gresley Pacific steam locomotives.
LNER Class A4 60034 Lord Faringdon was one of 35 Doncaster built Class A4 Gresley Pacific steam locomotives.
Stoke Bank is an inclined stretch of the East Coast Main Line (ECML) between Peterborough and Grantham. It is named after the village of Stoke Rochford, close to Stoke Summit, which at 345 feet (105 m) above sea level is the highest point of the ECML between London King's Cross and Berwick-upon-Tweed. It is not however, the highest point of the entire ECML, which is Grantshouse Summit between Berwick and Edinburgh at 400 feet (120 m).
LNER Class A3 2750 Papyrus was a 4-6-2 "Pacific" steam locomotive built for the London and North Eastern Railway (LNER) at Doncaster Works to a design of Nigel Gresley, entering service in March 1929. Primarily used to haul express passenger trains on the East Coast Main Line by LNER and its successor, British Railways, it is notable for achieving what was at the time a world record-breaking speed for a steam locomotive of 108 mph on 5 March, 1935. A fictionalized account based on the locomotive's service history and speed record, 2750: Legend of a Locomotive by H.C. Webster, was published in 1953 and reprinted in 2016.
References
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↑ Marsden, Richard. "The Gresley A4 Pacifics". LNER Encyclopedia. Winwaed Software Technology LLC. Retrieved 18 October 2020.
↑ Hughes, Geoffrey (2001). Sir Nigel Gresley: The Engineer and his Family. The Oakwood Press. pp.128–129. ISBN0-85361-579-9.
↑ Nock, O.S. (1945). The Locomotives of Sir Nigel Gresley. London: The Railway Publishing Co. p.129.
1 2 Allen, Cecil J. Locomotive Practice & Performance.
↑ Robertson, Kevin (2007). The Leader Project: Fiasco or Triumph?. Oxford: Oxford Publishing Company. ISBN978-0-86093-606-0.
↑ Hughes, Geoffrey (2001). Sir Nigel Gresley: The Engineer and his Family. The Oakwood Press. p.147. ISBN0-85361-579-9.
↑ Jones, Robin (2013). Mallard 75. Horncastle: Mortons Media Group Ltd. p.54. ISBN978-1-909128-15-6.
↑ Tuplin, W.A; Allen, George. British Steam since 1900. Unwin / Pan Books.[pageneeded]
↑ Nock, O.S. (1985). British Locomotives of the 20th Century vol 3: 1960–the present day. London: Guild Publishing/Book Club Associates. pp.89–91. CN9613.
↑ Farr, Keith (July 2013). Pigott, Nick (ed.). "Practice & Performance: New Light on ... Mallard the Magnificent". The Railway Magazine. Vol.159, no.1347. Horncastle: Mortons Media Group. pp.16–17. ISSN0033-8923.
↑ Marsden, Richard. "The Gresley A4 Pacifics". LNER Encyclopedia. Winwaed Software Technology LLC. Retrieved 28 October 2020.
↑ Scott, Ron; Reed, Brian (1971). "Gresley A4s". Loco Profile. No.19. Berks UK: Profile Publications. p.166.
↑ Rogers, Col. H.C.B. (1979). Thompson & Peppercorn Locomotive Engineers. London UK: Ian Allan. p.52. ISBN0-7110-0910-4.
↑ Ian Allan (1946). The ABC of L.N.E.R. Locomotives (Renumberinged.).
↑ Ramsay, John; Hammond, Pat (2002) [1998]. King, John (ed.). Ramsay's British Model Trains Catalogue (3rded.). Felixstowe: Swapmeet Publications. pp.298, 302, 33. ISBN0-9528352-7-4.
↑ "Hornby's new A4 and Gresley coaches unveiled at the NRM". British Railway Modelling. Vol.12, no.8. Bourne: Warners Group Publications. November 2004. p.36. ISSN0968-0764. OCLC1135061879.
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