Page "Shinkansen" Paragraph 11

Following the end of World War II, high-speed rail was forgotten for several years while traffic of passengers and freight steadily increased on the conventional Tōkaidō Main Line along with the reconstruction of Japanese industry and economy.

By the mid-1950s the Tōkaidō Line was operating at full capacity, and the Ministry of Railways decided to revisit the Shinkansen project.

In 1957, Odakyu Electric Railway introduced its 3000 series SE " Romancecar " train, setting a world speed record of for a narrow gauge train.

This train gave designers the confidence that they could safely build an even faster standard gauge train.

Thus the first Shinkansen, the 0 series, was built on the success of the Romancecar.