JNR Class EF55
The Class EF55 is a 2Co+Co1 wheel arrangement electric locomotive type consisting of three locomotives built in 1936 by Hitachi, Kawasaki, and Tōyō Electric in Japan. They were nicknamed "hippos " or "monster shoes " in the 1930s, and later in the 1980s "Moomin".
Design
Streamlined designs were adopted for railway rolling stock worldwide in the 1930s, and the Japanese Government Railways tested such a design on a Class C53 locomotive in 1934. It was then decided that 20 Class C55 steam locomotives would be built with a streamlined design. In the same year, the Tanna Tunnel opened on the Tokaido Main Line, and all express trains switched from the mountainous and detouring original route. Because of the length of the tunnel, steam locomotives were eliminated from operating through it, and a new class of mainline electric express locomotives was needed to replace the Class C51 and C53, which hauled the Tsubame and Fuji 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. 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. However, using turntables to keep the streamlined end at the front proved inefficient for regular operations. As a result, the Class EF56 and EF57 locomotives reverted to boxier designs, though the post-war EF58 brought back a more streamlined look. With an operational speed of 95 km/h, the EF55 surpassed 120 km/h during a trial run.