High-speed rail
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 and existing lines in excess of are widely considered to be high-speed, with some extending the definition to include lower speeds 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.
Express trains in India
Superfast Express trains are express trains which make still fewer stops, as compared to ordinary express trains, achieving still shorter journey times. Tickets cost more than ordinary express trains as they have "superfast surcharge" added to them. Trains with an average speed, excluding halts, equaling or exceeding ( until the early 1990s) on both up and down journeys fall into the this category and are numbered with a prefix of 12 or 22 or 20 (previously 2). Including halts the average speed often is below 55 km/h. In some cases, trains run superfast where there is an overlapping express service available, and run regular express trains where there is no supplementary express service.