The JNR Class HD53 was a proposed 4-8-4 Northern-type streamlined steam locomotive intended to be operated by the Japanese National Railways.
History[]
The Class HD53s were designed by the Japanese Ministry of Railways as part of the Japanese bullet train project, which was ultimately canceled due to the onset of the Pacific War and none were ultimately produced. Very few details of the train are available, even in design drawings. As such, many features are unknown, including valve gear and the number of cylinders; there have been models of the locomotive, but these make assumptions as to what the locomotive could have actually looked like if it were completed.
The train was intended to go 200 km/h (124 mph) at least, though there is some skepticism as to whether the locomotives could have achieved these speeds with Japan's infrastructure at the time. Shigenobu Usui, someone who has had numerous exchanges with JNR and JGR employees, dismisses the HD53 project as simply a "desk theory". The Railway Museum in Saitama exhibits the design drawings of the HD53, as well as the HC51 steam locomotive and HEH50 electric locomotive also intended for the bullet train project.