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The London and North Western Railway (LNWR) 7 ft 6 in Single 2-2-2 class was a type of express passenger locomotive designed by John Ramsbottom. The class is better known as the Problem class for the first locomotive built, or the Lady of the Lake class for the example that was displayed at the International Exhibition of 1862. The first examples were built shortly after the acquisition of the Chester and Holyhead Railway by the LNWR, and primarily saw use on the Irish Mail route from London to Holyhead. They were the first locomotives to be fitted with water scoops, which could refill the tender from water troughs between the tracks without stopping. One such locomotive, No. 229 ''Watt'', was the first to use them in non-stop run from Holyhead to Stafford in 1862, while conveying despatches relating to the Trent Affair. ==Design== The ''Lady of the Lake'' class was the second type of locomotive designed by Ramsbottom. It was typical of express passenger locomotives of its era in having a single driving axle with large ( in this instance) driving wheels to achieve high speeds, while avoiding the friction associated with coupled driving wheels. (Coupling was done primarily on goods locomotives, where tractive effort was more important than speed.) The locomotives bore a resemblance to 2-2-2 designs by Patrick Stirling and Joseph Beattie, yet could also be regarded as a development of Alexander Allan's designs under Ramsbottom's predecessor, Francis Trevithick. They has an open cab, a smokebox door that opened vertically, and open slots on the "splashers" that covered the driving wheels.〔(【引用サイトリンク】title='Lady of the Lake' class express passenger engines )〕 Like Ramsbottom's earlier DX Goods design, the Lady of the Lake class made use of the Stephenson valve gear and his own screw design of reversing gear. These locomotives saw the first use of Henri Giffard's steam injector in Britain, as well as the use of a water scoop. They were all painted in the green livery used by the Northern Division. The first locomotive built, No. 184 ''Problem'', was reputed to have gained the name because of the problem of getting the new injector to work, but the first ten engines (of which ''Problem'' was one) were fitted with a traditional crosshead pump. Her name may have a more mathematical origin, as the DX Goods locomotive No. 183 was given the name ''Theorem''. The first locomotives built were given tenders, but with the introduction of water scoops for refilling en-route they were replaced with tenders.〔 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「LNWR Lady of the Lake Class」の詳細全文を読む スポンサード リンク
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