HSR-350x, alternatively called G7, KHST or NG-KTX, and later officially renamed Hanvit 350, is a South Korean experimental high-speed train. It was developed and built in a joint project of government research institutes, universities and private companies that started in 1996, which aimed to reduce import dependence in high-speed rail technology. New components developed for the HSR-350x included motors, electronics, and the carbody of passenger cars. Test runs were conducted between 2002 and 2008. The experimental train achieved the South Korean rail speed record of 352.4 km/h (219.0 mph) in 2004. The HSR-350x was the basis for Korail's KTX-II (KTX-Sancheon) commercial high-speed trains.
When South Korea started its high-speed rail project, rolling stock and infrastructure was built in the framework of a technology transfer agreement between GEC-Alsthom (today Alstom), the main maker of French TGV high-speed trains, and South Korean companies. The first trains for Korea Train Express service, the KTX-I, were derived from the TGV Réseau, and built both by Alstom and Rotem (today Hyundai Rotem).
High-speed rail is a type of rail transport that operates significantly faster than traditional rail traffic, using an integrated system of specialized rolling stock and dedicated tracks. While there is no single standard that applies worldwide, new lines in excess of 250 km/h and existing lines in excess of 200 km/h are widely considered to be high-speed, with some extending the definition to include much lower speeds (e.g. 160 km/h) in areas for which these speeds still represent significant improvements. The first such system began operations in Japan in 1964 and was widely known as the bullet train. High-speed trains normally operate on standard gauge tracks of continuously welded rail on grade-separated right-of-way that incorporates a large turning radius in its design.
Many countries have developed high-speed rail to connect major cities, including Austria, Belgium, China, France, Germany, Italy, Japan, Poland, Portugal, Russia, South Korea, Spain, Sweden, Taiwan, Turkey, United Kingdom, United States and Uzbekistan. Only in Europe does HSR cross international borders. China has 19,000 km of HSR as of December 2015, accounting for two thirds of the world's total.
The abbreviation HSR may stand for: