minutes, as opposed to days. They run more frequently than long distance trains, and are often used by commuters. Short distance passenger trains specifically designed for commuters are known as commuter rail. High speed trains High speed trains are designed to be much faster than conventional trains, and typically run on their own separate tracks than other, slower trains. The first high speed train was the Japanese Shinkansen, which opened in 1964. In the 21st century, services such as the French TGV and German Intercity Express are competitive with airplanes in travel time over short to medium distances. A subset of high speed trains are higher speed trains, which bridge the gap between conventional and high speed trains, and travel at speeds between the two. Examples include the Northeast Regional in the United States, the Gatimaan Express in India, and the KTM ETS in Malaysia. Rapid transit trains A number of types of trains are used to provide rapid transit to urban areas. These are distinct from traditional passenger trains in that they operate more frequently, typically do not share tracks with freight trains, and cover relatively short distances. Many different kinds of systems are in use globally. Rapid transit trains that operate in tunnels below ground are known as subways, undergrounds, or metros. Elevated railways operate on viaducts or bridges above the ground, often on top of city streets. "Metro" may also refer to rapid transit that operates at ground level. In many systems, two or even all three of these types may exist on different portions of a network. Trams Trams, also known in North America as streetcars, typically operate on or parallel to streets in cities, with frequent stops and a high frequency of service. Light rail Light rail is a catchall term for a variety of systems, which may include characteristics of trams, passenger trains, and rapid transit systems. Specialized trains There are a number of specialized trains which differ from the traditional definition of a train as a set of vehicles which travels on two rails. Monorail Monorails were developed to meet medium-demand traffic in urban transit, and consist of a train running on a single rail, typically elevated. Monorails represent a small proportion of the train systems in use worldwide. Almost all monorail trains use linear induction motors. Maglev To achieve much faster operation over , maglev technology has been researched since the early