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The LMS (Northern Counties Committee) Class A1 4-4-0 passenger steam locomotives were rebuilds of Belfast and Northern Counties Railway Class A two-cylinder compound locomotives. They operated services throughout the NCC’s broad gauge system in the north-east of Ireland. == History == The Class A1 locomotives were rebuilds of the Class A "Heavy Compounds" that had been designed by the BNCR Locomotive Engineer Bowman Malcolm. The first Class A locomotive had been built by the BNCR at York Road, Belfast in 1901 shortly before amalgamation with the Midland Railway and building continued with the Midland Railway constructing six at their Derby works. The locomotives were built as two-cylinder compounds using the Worsdell-von Borries system, the high pressure cylinders having a diameter of and low pressure ones of , both with stroke. Following the end of World War I the state of the locomotives operating in Northern Ireland was well below that which was needed to run the services effectively; many needed replacing but, however, cost was a major factor. It was decided to implement a "Renewal Programme" in which, not only would new locomotives be built but also suitable classes of locomotives would be rebuilt, in the main following the style of the Midland Railway and the LMS. As part of this "Renewal Programme" members of Class A were rebuilt as two-cylinder simples (i.e. not compounds). Those reclassified as Class A1 were rebuilt with a Midland Railway type RG6 boiler and new cylinders both of diameter by stroke. The boiler was higher pitched than the original to allow the firebox and ash pan to clear the rear driving wheel axle and an extension of to the smokebox saddle was needed to offer support. Although the effect was less striking than that of the similarly rebuilt Class B3, the modified appearance was such that these locomotives would be included among those that gained the nickname of "Whippet" because of a perceived resemblance to the racing dog. All the class were officially named after mountains although that allocated to No. 58, ''Lurigethan'', was never carried. The majority of the Class A1 engines were coupled to what was known as the "Standard" tender which could carry of coal and of water. No.34, however, ran with one of the three "Medium" tenders that had a water capacity and No.62 acquired a spare built up tender with a capacity of . No.58 acquired a tender cab which led to her being a regular visitor on the Dungiven branch where tender first running was required. Nos.33, 58 and 69 later received boilers with a working pressure of in place of . This led to their being allocated to the Belfast area during the late 1930s where duties were more onerous. No.33 was shedded at York Road while the other two were at Larne. No.65 worked in a spare capacity at York Road and No.62 was based at Cookstown. The builders plates showing dates in the late 1920s and early 1930s belied the age of these engines and the heavy traffic that they handled during World War II showed up their weaknesses more than newly built locomotives. Nevertheless, the majority of the class survived to be taken into Ulster Transport Authority stock and were scrapped in the mid 1950s. 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「NCC Class A1」の詳細全文を読む スポンサード リンク
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