Japan is where regular, high-speed railways were born. The country's Shinkansen ('Bullet Train') network has been developed over more than 35 years, and covers all main trunk routes.
The network centres on the capital Tokyo, with lines to the west and north of this densely-populated nation. New Shinkansen variants are still under development, maintaining the country's pre-eminent technological position.
The first line to see these ground-breaking trains was from Tokyo to Osaka, the Tokaido Shinkansen, opened in October 1964. Initially, the trains ran at up to 200km/h (125mph), but this has been increased with improvements in infrastructure, signalling and maintenance.
The second generation Shinkansen was introduced in 1972 between Shin-Osaka and Okayama, three years later being extended to Hakata. Infrastructure improvements later allowed line speeds to be increased to 220km/h.
The first Shinkansen to the north of the country began operating in 1982. These were the Tohoku Shinkansen, from Tokyo to Morioka, and the Joetsu, to Niigata. Northbound services have been expanded, with the introduction of the Yamagata Shinkansen from Fukushima to Yamagata, the Akita Shinkansen between Morioka and Akita, and the Hokuriku Shinkansen, from Takasaki to Nagano.
Operating such an intensively used, high-speed railway creates enormous strains on the infrastructure, and as a result, around a third of all costs are swallowed up in maintenance.
Shinkansen run largely on conventional steel rail mounted on concrete sleepers, but the fastest services use dedicated tracks to avoid conflict with slower trains.
Shinkansen trains run on two different gauges - 1,067mm and 1,435mm - which precludes each part of the system from using the other's trains. However, many of the narrower gauge routes are to be converted to 1,435mm, and JR East finished conversion of its Yamagata-Shinjo route in December 1999.
Signalling is largely fixed block, although with such high line speeds, sections are much longer than is standard elsewhere.
A regular clock-face departure pattern for most services helps maintain a high level of reliability, but, in the event of emergencies, train crews are in constant contact with their nearest control centre.
Information systems on newer variants of Shinkansen trains are proving much more reliable than previously, thanks to their use of much shorter cable lengths.
Three types of trains operate on the Shinkansen routes. Nozomi are the fastest and most modern trains - the dramatically-styled 500 Series. The type is distinguished by its 15 metre-long power car nose, giving an extremely aerodynamic profile. The driver's cab has a dome canopy, to allow excellent forward vision.
The 500 Series also boasts an innovative pantograph design, shaped like a wing, which also helps reduce wind resistance at high speed. Drivers' instruments are all laid out in groups according to their function. Extensive soundproofing means there is little sensation of speed inside trains, and wind noise is at a minimum.
Two major expansions of the Shinkansen network remain a priority. Northbound services are planned to be extended to Sapporo, on the island of Hokkaido, while the JR-West services are earmarked on the Sanyo Shinkansen network around Fukuoka on the island of Kyushu. The latter involves a new 211km line from Funagoya to Kagoshima, on which work was under way at the turn of the century.
The next candidate is the 59km of the Nagano Shinkansen from Nagano to Joetsu, with plans existing to eventually extend this to Komatsu via Toyama and Kanazawa.
Major experiments are also being conducted into the use of magnetic levitation (Maglev) technology, on which magnetic power is used to levitate the vehicles, and propelled by linear motors, which gives potential for even higher speeds, by eliminating friction and vibration.
The Japanese government is currently evaulating the results of a three-year testing programme for possible future high-speed developments.