Class EF55 | |||||||||||||||||||||||||||
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![]() EF55 1 atMatsumoto Station, October 2003 | |||||||||||||||||||||||||||
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TheClass EF55 (EF55形) is a 2Co+Co1 wheel arrangementelectric locomotive type consisting of three locomotives built in 1936 byHitachi,Kawasaki, and Tōyō Electric in Japan.[2] They were nicknamed "hippos (kaba)" or "monster shoes (kutsu no bakemono)" in the 1930s, and later in the 1980s "Moomin".[3]
Streamlined designs were adopted for railway rolling stock worldwide in the 1930s, and theJapanese Government Railways (JGR) tested such a design on aClass C53 locomotive in 1934. It was then decided that 20Class C55 steam locomotives would be built with a streamlined design. In the same year, theTanna Tunnel opened on theTokaido Main Line, and all express trains switched from the mountainous and detouringoriginal route. Because of the length of the tunnel (8 km), steam locomotives were eliminated from operating through it, and a new class of mainline electric express locomotives was needed to replace theClass C51 and C53, which hauled theTsubame andFuji services.
As such, the Class EF55 were built with a streamlined design. Although based on the earlier EF53 design, the EF55s based on a unique non-symmetrical wheel arrangement with a streamlined cab at only one end. The number 2 end had a traditional-style cab with access deck.[1] The use of rivets and bolts were kept to a minimum, and welding was used to create a smooth surface. A 1936 trial showed a 9% reduction in air resistance when the locomotives ran with the streamlined end at the front.[4] However, using turntables to keep the streamlined end at the front proved inefficient for regular operations. As a result, the Class EF56 andEF57 locomotives reverted to boxier designs, though the post-warEF58 brought back a more streamlined look. With an operational speed of 95 km/h, the EF55 surpassed 120 km/h during a trial run.[2]
All EF55s were based atNumazu depot from 1936, and were operated on the Tokaido Line until 1952, when they were moved toTakasaki depot on theTakasaki Line. The need to turn locomotives into regular use proved to be the downfall of this small class,[2] and the locomotives were placed in storage in 1958, and then officially withdrawn in 1964. Following withdrawal, EF55 1 was moved to the former Chūō Railway Institute nearNishi-Kokubunji Station for apprentice training purposes.[2] EF55 3 was cannibalized to donate motors and other components to the ED30 prototype AC/DC electric locomotive, and EF55 2 was also cut up shortly after.[2]
EF55 1 was designated as an important piece of railway heritage in 1978, and was subsequently restored to running condition, re-entering service in 1986 for use hauling special event trains.[2] It was operated byJR East, based at Takasaki depot, until it was finally withdrawn in January 2009. EF55 1 was moved from Takasaki toOmiya in January 2015,[5] and exhibited at JR East'sRailway Museum from 12 April.[6]