JAPAN JNR Electric multiple unit of 581,583 series.

The sleeping car was driven from a viewpoint of silence in the coach which an engine tows. Therefore, high-speed operations were impossible for sleeping cars on the railroads of Japan.
Japan was in a growth phase of advanced economy in the 1960s. Thereby, the demand of transportation of the railroads increased very much. Since the speed of sleeping cars was slow, the increase in the number of train was difficult. Furthermore, since a sleeping car can be used only at night, it had run short of garages. It became impossible for as trains for the daytime increased the need to use a garage. Furthermore, the expense required to manufacture new vehicles also ran short because having separate coaches for daytime and night time needed to be manufactured separately.
Then, JNR designed an Electric multiple unit for a bed which could be used for both day and night. The Electric multiple unit of the 581 series appeared in 1967. This was able to run the electrified section of a direct current, and the electrified section of 60htz of an alternating current. This Electric multiple unit was converted in 1968 so that the electrified section of 50Htz of an alternating current could also run. This is the 583 series. The Electric multiple unit of this bed enabled the 120-km/h fastest operation in the old railroad line of Japan in those days. This was initially used for the limited express Gekkou (English is moonlight) for Hakata Station from Shin-Osaka Station.