The popular English name bullet train is a literal translation of the Japanese term dangan ressha, a nickname given to the project while it was initially being discussed in the 1930s. The name stuck because of the original 0 Series Shinkansen's resemblance to a bullet and its high speed.
The Shinkansen name was first formally used in 1940 for a proposed standard gauge passenger and freight line between Tokyo and Shimonoseki that would have used steam and electric locomotives with a top speed of 200 km/h (120 mph). Over the next three years, the Ministry of Railways drew up more ambitious plans to extend the line to Beijing (through a tunnel to Korea) and even Singapore, and build connections to the Trans-Siberian Railway and other trunk lines in Asia. These plans were abandoned in 1943 as Japan's position in World War II worsened. However, some construction did commence on the line; several tunnels on the present-day Shinkansen date to the war-era project.
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 145 km/h (90 mph) 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.
In 1950s, it was widely believed that railways would soon be outdated and replaced by air travel and highways as in America and many countries in Europe. However, Shinji Sogo, President of Japan National Railways, insisted strongly on the possibility of high-speed rail, and the Shinkansen project was implemented.
Government approval came in December 1958, and construction of the first segment of the Tōkaidō Shinkansen between Tokyo and Osaka started in April 1959. The cost of constructing the Shinkansen was at first estimated at nearly 200 billion yen, which was raised in the form of a government loan, railway bonds and a low-interest loan of US$80 million from the World Bank. Initial cost estimates, however, had been deliberately understated and the actual figures were nearly double at about 400 billion yen. As the budget shortfall became clear in 1963, Sogo resigned to take responsibility.
Shinkansen literally means new trunk line, referring to the tracks, but the name is widely used inside and outside Japan to refer to the trains as well as the system as a whole. The name Superexpress, initially used for Hikari trains, was retired in 1972 but is still used in English-language announcements and signage.
The Tōkaidō Shinkansen is the world's busiest high-speed rail line. Carrying 151 million passengers a year (March 2008), it has transported more passengers (over 4 billion, network over 6 billion) than any other high speed line in the world. Between Tokyo and Osaka, the two largest metropolises in Japan, up to thirteen trains per hour with sixteen cars each (1,323 seats capacity) run in each direction with a minimum headway of three minutes between trains. Though largely a long-distance transport system, the Shinkansen also serves commuters who travel to work in metropolitan areas from outlying cities.
Japan was the first country to build dedicated railway lines for high speed travel. Because of the mountainous terrain, the existing network consisted of 3 ft 6 in (1,067 mm) narrow gauge lines, which generally took indirect routes and could not be adapted to higher speeds. Consequently, Japan had a greater need for new high speed lines than countries where the existing standard gauge or broad gauge rail system had more upgrade potential.
Among the key people credited with the construction of the first Shinkansen are – Hideo Shima, the Chief Engineer, and Shinji Sogo, the first President of Japan National Railways (JNR) who managed to persuade politicians to back the plan. Other significant people responsible for its technical development were – Tadanao Miki, Tadashi Matsudaira, and Hajime Kawanabe based at the Railway Technology Research Institute (RTRI), part of JNR. They were responsible for much of the technical development of the first line - the Tokaido Shinkansen. All three had worked on aircraft design during World War II.
To enable high-speed operation, Shinkansen uses advanced technologies compared with conventional rail, and it achieved not only high speed but also a high standard of safety and comfort. Its success has influenced other railways in the world and the importance and advantage of high-speed rail has consequently been revalued.
Shinkansen routes are completely separate from conventional rail lines (except Mini-shinkansen which goes through to conventional lines). Consequently, Shinkansen is not affected by slower local or freight trains and has the capacity to operate many high-speed trains punctually. The lines have been built without road crossings at grade.Tracks are strictly off-limits with penalties against trespassing strictly regulated by law. It uses tunnels and viaducts to go through and over obstacles rather than around them, with a minimum curve radius of 4,000 meters (2,500 meters on the oldest Tōkaidō Shinkansen).
The Shinkansen uses 1,435 mm standard gauge in contrast to the 1,067 mm narrow gauge of older lines. Continuous welded rail and Swingnose crossing are employed, eliminating gaps at turnouts and crossings. Long rails are used, joined by expansion joints to minimize gauge fluctuation due to thermal elongation and shrinkage.
A combination of ballasted and slab track are used, with slab track exclusively employed on concrete bed sections such as viaducts and tunnels. Slab track is significantly more cost-effective in tunnel sections, since the lower track height reduces the cross-sectional area of the tunnel, thereby reducing construction costs by up to 30%
The Shinkansen employs an ATC (Automatic Train Control) system, eliminating the need for trackside signals. It uses a comprehensive system of Automatic Train Protection. Centralized traffic control manages all train operations, and all tasks relating to train movement, track, station and schedule are networked and computerized.
Shinkansen uses a 25,000 V AC overhead power supply (20,000 V AC on Mini-shinkansen lines), to overcome the limitations of the 1,500 V Direct current used on the existing electrified narrow-gauge system. Power is distributed along the axles of the train to reduce the heavy axle loads under single power cars.
Shinkansen trains are electric multiple unit style, offering high acceleration and deceleration, and reduced damage to the track because of lighter vehicles. The coaches are air-sealed to ensure stable air pressure when entering tunnels at high speed.
The Shinkansen is very reliable thanks to several factors, including its near-total separation from slower traffic. In 2003, JR Central reported that the Shinkansen's average arrival time was within six seconds of the scheduled time. This includes all natural and human accidents and errors and was calculated over roughly 160,000 Shinkansen trips completed. The previous record, from 1997, was 18 seconds.