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Number 4468 ''Mallard'' is a London and North Eastern Railway Class A4 4-6-2 Pacific steam locomotive built at Doncaster, England in 1938. It is historically significant as the holder of the world speed record for steam locomotives.〔(【引用サイトリンク】title=Mallard 75 )〕 The A4 class was designed by Sir Nigel Gresley to power high-speed streamlined trains. The wind-tunnel-tested, aerodynamic body and high power allowed the class to reach speeds of over , although in everyday service it was relatively uncommon for any steam-hauled service in the UK to reach even 90 mph, much less 100. ''Mallard'' covered almost one and a half million miles (2.4 million km) before it was retired in 1963. It was restored to working order in the 1980s, but has not operated since, apart from hauling some specials between York and Scarborough in July 1986 and a couple of runs between York and Harrogate/Leeds around Easter 1987. ''Mallard'' is now part of the National Collection at the United Kingdom's National Railway Museum in York. On the weekend of 5 July 2008, ''Mallard'' was taken outside for the first time in years and displayed beside the three other A4s that are resident in the UK, thus reuniting them for the first time since preservation. It departed the museum for Locomotion, the NRM's outbase at Shildon on 23 June 2010, where it was a static exhibit, until it was hauled back to York on 19 July 2011 and put back on display in its original location in the Great Hall. The locomotive is long and weighs 165 tons, including the tender. It is painted LNER garter blue with red wheels and steel rims. ==Record== ''Mallard'' is the holder of the world speed record for steam locomotives at . The record was achieved on 3 July 1938 on the slight downward grade of Stoke Bank south of Grantham on the East Coast Main Line, and the highest speed was recorded at milepost 90¼, between Little Bytham and Essendine. It broke the German (DRG Class 05) 002's 1936 record of . The record attempt was carried out during the trials of a new quick acting brake (the Westinghouse "QSA" brake). ''Mallard'' was a very good vehicle for such an endeavour. The A4 class was designed for sustained 100+ mph (160+ km/h) running and ''Mallard'' was one of a few of the class that were built with a double chimney and double Kylchap blastpipe, which made for improved draughting and better exhaust flow at speed. (The remainder of the class were retro-fitted in the late 1950s). The A4's three-cylinder design made for stability at speed, and the large driving wheels meant that the maximum revolutions per minute was within the capabilities of the technology of the day. ''Mallard'' was four months old, meaning that it was sufficiently broken-in to run freely, but not overly worn. Selected to crew the locomotive on its record attempt were driver Joseph Duddington (a man renowned within the LNER for taking calculated risks) and fireman Thomas Bray. In the words of Rob Gwynne, Assistant Curator of Rail Vehicles at the National Railway Museum; The locomotive had previously had problems with the big end bearing for the middle cylinder, so the big end was fitted with a "stink bomb" of aniseed oil which would be released if the bearing overheated. Shortly after attaining the record speed, the middle big end did overheat and ''Mallard'' had to limp onwards to Peterborough. It then travelled to Doncaster for repair. This had been foreseen by the publicity department, who had many pictures taken for the press, in case ''Mallard'' did not make it back to Kings Cross. The (Edwardian period) Ivatt Atlantic that replaced ''Mallard'' at Peterborough was only just in sight when the head of publicity started handing out the pictures. Stoke Bank has a gradient of between 1:178 and 1:200. ''Mallard'', pulling a dynamometer car and six coaches, topped Stoke Summit at and accelerated downhill. The speeds at the end of each mile (1.6 km) from the summit were recorded as: 87½, 96½, 104, 107, 111½, 116 and 119 mph (141, 155, 167, 172, 179, 187 and 192 km/h); half-mile (800 m) readings after that gave 120¾, 122½, 123, 124¼ and finally 125 mph (194, 197, 198, 200 and 201 km/h). The speed recorded by instruments in the dynamometer car reached a momentary maximum of . On arrival at King's Cross (just after the run) driver Joe Duddington and Inspector Sid Jenkins were quoted as saying that they thought a speed of 130 mph would have been possible if the train had not had to slow for the junctions at Essendine. In addition at the time of the run there was a permanent way restriction to 15 mph just north of Grantham which slowed the train as they sought to build up maximum speed before reaching the high speed downhill section just beyond Stoke tunnel. On 3 July 2013, ''Mallard'' celebrated 75 years since achieving the world speed record, and to help commemorate this date all six surviving Class A4 locomotives were brought together around the turntable in the Great Hall of the National Railway Museum at York for a two-week 'great gathering'. The visitors include three UK based, privately owned engines in 4464 ''Bittern'', 60007 ''Sir Nigel Gresley'' and 60009 ''Union of South Africa''. Mallard's two internationally based sisters, 60008 ''Dwight D. Eisenhower'' and 60010 ''Dominion of Canada'', were present after completing extensive transatlantic journeys, and undergoing cosmetic restoration at the NRM's workshops.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「LNER Class A4 4468 Mallard」の詳細全文を読む スポンサード リンク
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