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The LNER W1 No. 10000 (also known as the ''Hush-Hush'' due to its secrecy and "Galloping Sausage" before rebuild due to its shape〔http://www.pegnsean.net/~railwayseries/database.htm#DATDE〕) was an experimental steam locomotive fitted with a high pressure water-tube boiler. Nigel Gresley was impressed by the results of using high-pressure steam in marine applications and so in 1924 he approached Harold Yarrow of shipyard & boilermakers Yarrow & Company of Glasgow to design a suitable boiler for a railway locomotive, based on Yarrow's design. == Boiler == The boiler was not the usual Yarrow design. In operation, particularly its circulation paths, the boiler had more in common with other three-drum designs such as the Woolnough. It has also been described as an evolution of the Brotan-Deffner water-tube firebox, with the firebox extended to become the entire boiler. The boiler resembled two elongated marine Yarrow boilers, joined end to end. Both had the usual Yarrow triangular arrangement of a central large steam drum above two separated water drums, linked by multiple rows of slightly curved tubes. The rearward "firebox" area was wide and spanned the frames, placing the water drums at the limits of the loading gauge. The forward "boiler" region was narrow-set, with its water drums placed between the frames. The space outboard of the tubes formed a pair of exhaust flues leading forwards. A large space outside these flue walls but inside the boiler casing was used as an air duct from the air inlet, a crude rectangular slot beneath the smokebox door, which had the effect of both pre-heating the combustion air and also cooling the outer casing to prevent overheating. Longitudinal superheater tubes were placed between the steam generating tubes. The third area forwards contained superheater headers, the regulators and the smokebox. The external boiler casing remained at much the same width throughout, giving an overall triangular, but curved, appearance. The lower edge of each section stepped upwards, and was obvious externally. Working pressure was of as opposed to the of the contemporary Gresley A1 locomotives. The heavy forgings for the main drums were built in Sheffield by the John Brown shipyard.〔Nock, British Steam Railway Locomotive, p. 106〕 The boiler was constructed and fitted to the frames by Yarrow in Glasgow, involving the rolling chassis being carried over the LMS, carefully sheeted over to avoid inspection by a rival railway company. This chassis was a 4-2-2-4 at this point, as the centre drivers and rods had not yet been fitted. The first works photographs, with the boiler cladding in grey, were taken in Glasgow, with a wooden dummy centre driver and coupling rod added for the photo. 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 W1」の詳細全文を読む スポンサード リンク
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