Seoul subway serving the Seoul Metropolitan Area is the longest subway system in the world. The total route length of the system extended as far as 940km as of 2013. The first line of the subway was opened in 1974 and the system presently incorporates 17 lines (excluding the Uijeongbu LRT and the recently opened Yongin Ever Line).
The subway system is operated by multiple operators including the state-owned Seoul Metro, Seoul Metropolitan Rapid Transit Corporation, Korail, Incheon Transit Corporation, and other private rapid transit operators. Many extension projects are under construction on the already extensive subway network. The annual ridership of the subway system in 2012 was a mammoth 2.518 billion making it the second busiest subway system after Tokyo subway.
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The 468km network of the Shanghai Metro makes it the world's second longest. Shanghai Metro is the third rapid transit system in Mainland China, after Beijing and Tianjin. Shanghai Shentong Metro operates the network through its four subdivisions.
The first line of the Shanghai Metro was opened in 1993, and the system is currently operated with 12 lines and 303 stations. Construction is underway to extend a few of the existing lines and add new lines to the system. The metro network is planned to be expanded up to a length of 877km with 22 lines. The annual ridership of the metro in 2012 was 2.276 billion.
Beijing Subway, China's oldest metro system, currently ranks as the world's third longest subway system comprising of 17 operatinglines spanning a total length of 456km. The subway system has been in operation since 1969 and is owned by the city of Beijing. State-owned Beijing Mass Transit Railway Operation operates 14 lines of the system, while the other three lines are operated by Beijing MTR through a public-private joint venture with the Hong Kong MTR.
Eight of the 17 lines of the system serve the Beijing city's urban while the remaining nine lines offer connectivity to the suburbs. The network includes more than 270 stations and has an annual ridership of 2.46 billion (2012 estimate). Six new subway lines are expected to be operational on the system by 2016 and the total route length of the network is expected to exceed 1,000km by 2020.
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London Underground, commonly known as the Tube, with a total route length of 402km is the world's fourth longest subway system.It is also the oldest metro system in the world and has been operational since 1863. It comprises of 11 lines and 270 stations, and is operated by Transport for London (TfL).
The subway system provides inner-city metro services in Greater London and suburban railway services to some parts of Buckinghamshire, Hertfordshire and Essex counties. Surface lines comprise 54% of the system, while the rest 46% runs on sub-surface and deep-level tube lines. The annual ridership of the system was estimated at 1.17 billion in 2012. TfL has been carrying out major improvement programmes on the London Underground since 2007.
The New York subway is currently the world's fifth longest subway system, with a total route length of 368km. The rapid transit system, serving the New York City, commenced operation in 1904. It is owned by the City of New York and operated by the New York City Transit Authority, a subsidiary of the Metropolitan Transportation Authority.
The subway system is operated with 24 lines and 468 stations, and is currently touted as having more stations than any other metro system. About 60% of the stations in the system are underground. The annual ridership of the subway in 2012 was 1.665 billion. Times Sq-42, followed by Grand Central-42, was the busiest station of the subway network with an annual ridership of 62 million.
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The 317.5km long Moscow Metro is the sixth longest subway system in the world. It is mostly underground, and serves the city of Moscow and the neighbouring towns Krasnogorsk and Reutov. State-owned enterprise Moskovsky Metropoliten owns and operates the metro system.
The Moscow Metro is currently operated with 12 lines and 190 stations, and recorded an annual ridership of 2.389 billion in 2012. Lermontovsky Prospekt and Zhulebino are the two most recent stations inaugurated in November 2013 as part of the Tagansko-Krasnopresnenskaya line expansion. It is undergoing a major expansion programme to add 150km of line to the network by 2020.
Tokyo subway system ranks seventh among the world's longest subway systems. The total route length of the subway system as of2013 was 310km comprising of 13 lines and 290 stations. Private company Tokyo Metro operates nine lines and 184 stations, whereas Tokyo Metropolitan Bureau of Transportation, also known as the Toei Subway, operates the remaining four lines and 106 stations.
Tokyo subway is the busiest subway system in the world and recorded an annual ridership of 3.102 billion in 2012. Since the opening of first line in 1927, the Tokyo rapid transit system has been expanded to better serve the megacity with a population over 35 million as well as provide connections to suburban railway lines outside central Tokyo.
The Madrid Metro system serving Madrid, the capital city of Spain, is currently the world's eighth longest metro system. The Madrid Metro runs 293km long consisting of 13 lines and 300 stations. The first line of the system began operation in 1919. Metro de Madrid, under the administration of the autonomous community of Madrid, is the operator of the network.
The metro system is operated with more than 2,400 train sets, most of them are CAF metro trains. The annual ridership of the metro in 2012 was 628 million. The metro has been undergoing a new expansion and improvement plan since 2011, and is planned to be expanded by 24km by 2015.
Guangzhou Metro system serving the city of Guangzhou in the Guangdong Province of China is currently the ninth longest subway system in the world. The metro system has been operational since 1997 and currently measures 232km long. It currently consists of eight lines and 144 stations, and is operated by state-owned Guangzhou Metro Corporation.
Guangfo line, the first intercity underground metro line in China, is part of the Guangzhou metro and connects Guangzhou with Foshan. The annual ridership of the Guangzhou metro in 2012 was 1.825 billion. The metro network continues to be expanded with construction of new lines and expansion of the existing lines. The route length of the system is expected to exceed 600km by 2020.
Paris Metro serving the French capital city Paris and the Paris Metropolitan Area is the world's tenth longest metro system with total route length of 218km. Paris Metro is one of the oldest urban transit systems in the world; the first line of the metro was opened in 1900.
Paris Metro consists of 16 lines and 300 stations, most of them underground, and is operated by state-owned Régie Autonome des Transports Parisiens (RATP). Line 14 of the metro system, opened in 1998, is completely automated and driver-less. Extensions of the Lines 4, 12 and 14 are currently under construction. The metro is operated with 700 train units and has an annual ridership of 1.524 billion (2012 estimate).
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