It refers to a railway that allows trains to operate at higher speeds than conventional high-speed railways. There is no clear definition, and the concept is changing with technological advances. Following the opening of the Tokaido Shinkansen in 1964 and its success, railways themselves were reevaluated around the world, and efforts were made to increase speed and develop new high-speed railways. Generally, railways obtain thrust from the friction (adhesion) between the wheels and rails. As the speed increases, the friction between the wheels and rails decreases, and the thrust that can be transmitted also decreases. On the other hand, the running resistance that occurs during operation increases with speed. For this reason, when the Shinkansen was first opened, a speed of about 250 kilometers per hour was considered the limit for commercial operation. New railway systems that could run at speeds faster than this were called ultra-high-speed railways, and development was promoted in various countries by combining air levitation systems, magnetic levitation systems, and linear motor propulsion systems. However, it was later revealed that the judgment at the time that 250 kilometers per hour was the limit was incorrect, and that steel wheels and steel rail systems were capable of running at higher speeds, and development of higher speeds using the conventional steel wheel system progressed. Taking advantage of the 2008 Beijing Olympics, China achieved commercial operation at speeds of 350 kilometers per hour, and even faster speeds of 380 kilometers per hour and 400 kilometers per hour are becoming a reality. Currently, high-speed railways are defined as railways using steel wheels that run at speeds of 250 kilometers per hour or more. As a result, an increasing number of countries (France, Germany, Spain, Italy, China, etc.) have abandoned development of ultra-high-speed railways using new systems and are shifting to higher speeds using the proven steel wheel and steel rail system. At present, Japan is the only country aiming to realize ultra-high-speed railways by developing a new system. [Takuji Sasaki] Propulsion method and support/guidance methodUltra-high speed trains require the development of propulsion systems and car support/guidance systems. The following methods have been considered for each of these: [1] Propulsion system: (1) A system that uses propellers or jet engines to generate thrust, as in aircraft. (2) A linear turbine system that uses the principle of a turbine, with fixed blades on the ground and rotating blades on the train, to create linear motion. (3) A linear motor system that uses the principle of an electric motor to create linear motion. (4) A tube railway system that uses the difference in air pressure and gravity. [2] Support and guidance methods: (1) Wheel and rail system. (2) Air suspension system, the same as hovercraft. (3) Magnetic support and guidance system, which uses the attractive and repulsive forces of magnets. [Takuji Sasaki] History of overseas developmentGermany has been developing various types of systems, including superconducting magnetic levitation, normal conductive magnetic levitation, and air levitation, but later narrowed down to the normal conductive magnetic levitation linear synchronous motor system and carried out development experiments. Experimental runs of a practical-sized two-car experimental train, the TR06, have been carried out on the 31.5 km long Emsland experimental line. A practical line for this normal conductive magnetic levitation high-speed train, the Transrapid, was planned to open between Hamburg and Berlin in 2005, but due to financial difficulties, the plan was cancelled in February 2000. It was later considered as an access to Munich Airport, but was ultimately not adopted. Germany gave up on practical use of the train and shifted its focus to development of high-speed trains using conventional railway systems, such as the ICE3. Using technology from the German-Sino Transrapid company, an agreement was signed with Germany in 2001 to build a practical line of about 30 kilometers between Shanghai and Pudong International Airport, test runs began in December 2002, and commercial operations at a maximum speed of 430 kilometers per hour have been underway since 2004. This can be said to be the only ultra-high-speed railway in the world at present. France was actively involved in the development of the air-levitated Aérotrain, and built an 18-kilometer test line near Orléans, achieving a record speed of 425 kilometers per hour in 1974. However, construction of a commercial line using this method was postponed, and the country switched to high-speed operation of the TGV (Train Vehicle), a conventional railway method. In the United States , research and development has been carried out on a variety of support and guidance systems, including both air levitation and superconducting magnetic levitation, and propulsion systems such as linear motors, gas turbines, and vacuum tube railways, but none of these systems were put to practical use. Britain was working on developing an aerial hovertrain, but has not made any progress since.
[Takuji Sasaki] History of development in JapanFrom the beginning, development was focused on the magnetic levitation system. There were two types of projects depending on the development parent organization. The system developed by the Japanese National Railways, and then by JR Central and the Railway Technical Research Institute after the division and privatization, is the superconducting magnetic levitation linear synchronous motor system. In 1979 (Showa 54), the experimental car ML-500 achieved a speed of 517 kilometers per hour while running unmanned on the Miyazaki Test Line. Various experiments, including manned running, were conducted with the MLU001, which is closer to a practical model, and in February 1987, it achieved a manned world record of 400.8 kilometers per hour. Since 1990 (Heisei 2), it has been promoted as a national project, and development has been handed over to the Yamanashi Linear Test Line. Meanwhile, Japan Airlines, aiming to realize a high-speed transportation system linking airports and city centers, worked on the development of HSST (High Speed Surface Transport) using a normally conducting magnetically levitated linear induction motor. In 1985, an experimental vehicle, HSST-03, was run at the International Science and Technology Exposition held in Tsukuba Science City. However, due to factors such as profitability, practical application did not progress, and Japan Airlines withdrew from the HSST business. After that, they gave up on high-speed operation and instead used the technology as a medium-scale, medium-speed transportation system on Aichi Rapid Transit's Eastern Hill Line, "Linimo." [Takuji Sasaki] "Ultra-high-speed Shinkansen" by Takeshi Oku, Yoshiyasu Kyotani, and Toshio Sanuki (1971, Chuokoron-Shinsha) " "The Beginning of Research on Ultra-high-speed Land Transportation" by Tatsuo Nishigame (1999, Nihon Tosho Kankokai)" "How Fast Can the Shinkansen Run? by Takuji Sasaki (published in the May 2011 issue of JREA, Japan Railway Engineering Association)" [Reference] | | | |Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend |
従来の高速鉄道に比べ、さらに高速での列車運行を可能とする鉄道をいう。明確な定義はなく、その概念も、技術の進歩とともに変化している。 1964年(昭和39)の東海道新幹線の開業とその成功に伴い、世界各国で鉄道そのものが見直され、高速化や新しい高速鉄道開発への取組みが行われるようになった。一般に、鉄道は車輪とレールとの摩擦力(粘着力)によって推力を得ている。速度の増加にしたがって車輪とレールの摩擦力は低下し、伝達できる推力も低下してしまう。一方、走行に伴って生じる走行抵抗は速度とともに増大する。このため、新幹線開業当時は時速250キロメートル程度の速度が営業運転の限界速度と考えられた。これ以上の速度で走行する新たな鉄道システムを超高速鉄道とよび、空気浮上方式や磁気浮上方式とリニアモーター推進などを組み合せて、各国で開発が進められることとなった。しかし、その後、時速250キロメートルが限界であるという当時の判断は誤りで、鉄車輪と鉄レールシステムでより高速での走行が可能であることが明らかになり、従来の鉄車輪方式での高速化の開発が進むこととなった。2008年の北京オリンピック開催を機会に中国では時速350キロメートルでの営業も実現し、さらに高速となる時速380キロメートルや400キロメートルでの営業運転も現実のものになりつつある。現在では時速250キロメートル以上の高速で走行する鉄車輪方式の鉄道を高速鉄道と定義するようになっている。このため、新たなシステムを目ざした超高速鉄道の開発は取りやめて、実績のある鉄車輪と鉄レールシステムにおける高速化を目ざす方向に転換する国々(フランス、ドイツ、スペイン、イタリア、中国など)が増えることとなった。新たなシステムの開発によって超高速鉄道の実現を目ざす国は日本だけとなっているのが現状である。 [佐々木拓二] 推進方式と支持・案内方式超高速鉄道には、推進方式と車体の支持・案内方式の開発が必要である。それぞれ次のような方式が検討されてきた。 〔1〕推進方式 〔2〕支持・案内方式 [佐々木拓二] 海外における開発の経緯ドイツ 中国 フランス アメリカ イギリス
[佐々木拓二] 日本における開発の経緯当初から磁気浮上方式に絞って開発を行ってきた。開発母体に応じて二つの系統のプロジェクトがあった。日本国有鉄道が取り組み、分割・民営化後はJR東海と鉄道総合技術研究所が中心となって開発を行っているものは、超電導磁気浮上リニアシンクロナスモーター方式である。1979年(昭和54)に実験車ML-500の無人走行で時速517キロメートルを宮崎実験線で達成した。より実用型に近いMLU001により有人走行を含む各種の実験が行われ1987年2月には時速400.8キロメートルの有人世界記録を達成した。1990年(平成2)からは国家プロジェクトとして推進され、開発は山梨リニア実験線に引き継がれている。 一方、空港と都市中心部を結ぶ高速交通機関の実現を目ざした日本航空は、常電導磁気浮上リニアインダクションモーター方式のHSST(High Speed Surface Transport)の開発に取り組んだ。1985年に筑波研究学園都市(つくばけんきゅうがくえんとし)で開催された国際科学技術博覧会では実験車HSST-03が走行した。しかし、採算性などから実用化が進まず、日本航空はHSST事業から撤退した。その後、高速走行は断念して、中規模の中速輸送機関として、愛知高速交通の東部丘陵線「リニモLinimo」に、その技術が生かされることとなった。 [佐々木拓二] 『奥猛・京谷好泰・佐貫利雄著『超高速新幹線』(1971・中央公論社)』▽『西亀達夫著『「超高速陸上交通機関」研究の幕開け』(1999・日本図書刊行会)』▽『佐々木拓二著「新幹線はどこまで高速で走れるか」(『JREA』2011年5月号所収・日本鉄道技術協会)』 [参照項目] | | | |出典 小学館 日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について 情報 | 凡例 |
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