The Tōkaidō Shinkansen (東海道新幹線?) is a Japanese high-speed Shinkansen line, opened in 1964 between Tokyo and Shin-Ōsaka. It is operated by the Central Japan Railway Company (JR Central), and formerly by Japanese National Railways (JNR). It is the most heavily travelled high-speed rail route in the world by far; its cumulative ridership of 4.9 billion passengers dwarfs all other systems and lines worldwide.
The line was named a joint Historic Mechanical Engineering Landmark and IEEE Milestone by the American Society of Mechanical Engineers and the Institute of Electrical and Electronics Engineers in 2000.
The Tōkaidō Shinkansen line was originally conceived in 1940 as a 150 km/h (93 mph) dedicated railway between Tokyo and Shimonoseki, which would have been 50% faster than the fastest express train of the time. The beginning of World War II stalled the project in its early planning stages, although a few tunnels were dug that were later used in the Shinkansen route. Since the line goes through Japan's three largest metropolitan areas, it is the most heavily travelled of all Shinkansen routes.
Construction of the line began on 20 April 1959 under JNR president Shinji Sogō and chief engineer Hideo Shima. It was completed in 1964, with the first train travelling from Tokyo to Shin-Ōsaka on 1 October of that year at 210 km/h. The opening was timed to coincide with the 1964 Summer Olympics in Tokyo, which had already brought international attention to the country. Originally the line was referred to in English as the New Tōkaidō Line. It is named after the Tōkaidō route of Japan used for centuries. Speeds have been increased to 270 km/h today except for a lower limit applying between Tokyo and Shinagawa.
A new Shinkansen stop at Shinagawa Station opened in October 2003, accompanied by a major timetable change which increased the number of daily Nozomi services.
All Tōkaidō Shinkansen trains to and from Tokyo make station stops at Shinagawa and Shin-Yokohama. (Before March 2008, alternating Nozomi and Hikari services stopped at either or both of these stations.)
A new station, Minami-Biwako, was planned to open in 2012 between Maibara and Kyoto to allow a transfer to the Kusatsu Line. Construction started in May 2006, but in September 2006, the Otsu district court ruled that the ¥4.35 billion bond that Ritto city had issued to fund construction was illegal under the local finance law and had to be cancelled. The project was officially cancelled in October 2007.