Although the railroad played a significant role in the transportation of both passengers and freight during the 19th and early 20th cent., in the latter part of the 20th cent., the automobile and the aircraft eroded the railroad's importance for passenger travel until the introduction of high-speed rail. Faster than the automobile and more convenient than the airplane, high-speed passenger service was pioneered in Japan with the introduction of the Shinkansen, popularly known as the "bullet train," in 1964. The French Train à Grande Vitesse, or TGV, introduced the high-speed train to Europe in 1981. Other Continental countries soon followed—Italy (1988), Germany (1991), and Spain (1992)—and Great Britain began a high-speed service in 1984. It was not until 2000, however, that high-speed service began in the United States with the Acela Express, running between Washington, D.C., and Boston. Other countries that have or are developing high-speed rail lines include Australia, China, Finland, South Korea, Sweden, and Taiwan. China now has the most extensive high-speed rail network in the world. Maglev trains (see magnetic levitation) have been run experimentally on short tracks in several countries. A maglev line linking Shanghai's financial district with its new airport was opened in 2002; scheduled commericial operation began in 2004.
High-speed trains have operational speeds of 186 mi per hr (300 km per hr) or more. The non-maglev speed record, set by the French TGV Atlantique during tests, is 320 mi per hr (515 km per hr). A Japanese maglev train has reached 361 mi per hr (581 km per hr). To attain these speeds requires high-quality track, roadbed, and right of way. Among the features associated with high-speed trains are the absence of grade, or level, crossings; wide spacing between tracks; four tracks at through stations so that slower, local trains can be bypassed; concrete foundations topped by tarmac and then ballast to minimize movement of the track; curves with a radius greater than 3 mi (5 km); and the avoidance of tunnels.