The Munich U-Bahn () is an electric rail rapid transit network in Munich, Germany. The system began operation in 1971, and is operated by the municipally owned Münchner Verkehrsgesellschaft (MVG; Munich Transport Company). The network is integrated into the Münchner Verkehrs- und Tarifverbund (MVV; Munich Transport and Tariff Association) and interconnected with the Munich S-Bahn. The U-Bahn currently comprises eight lines, serving 96 stations (100 stations if four interchange stations with separate levels for different lines are counted twice), and encompassing of routes. Current routes There are eight lines: The network has of active route, and 100 stations. In 2014, 390 million passengers rode the U-Bahn. The trains operate at speeds up to , which is the top speed among German U-Bahns. There is no continuous operation during the night (break from 1 to 4 am, 2 to 4 am on weekends) except on special occasions such as New Year's Eve. Currently, only the U6 line crosses the municipal border to the town of Garching. Except for the lines U5 and U6, all lines operate completely below ground. U5 only comes above ground at the south terminus Neuperlach-Süd, U6 on the northern section from Studentenstadt (except Garching and Garching-Forschungszentrum stations and tunnels). There are three "line families", which each consist of two lines (not counting peak hour lines) that share a common track in the city centre. The schedules of these lines are coordinated to produce regular train intervals on the common section. Most stations have two tracks with an island platform between them. Of the single-line stations, only the stations Olympia-Einkaufszentrum (U1), Richard-Strauss-Straße (U4), Neuperlach Süd (U5), Garching-Hochbrück and Nordfriedhof (both U6) have side platforms. At the junction stations Scheidplatz and Innsbrucker Ring, the four tracks run in parallel on the same level, with two island platforms allowing cross-platform interchange. The stations Hauptbahnhof (lower level), where U1 and U2 branch into two different lines and Münchner Freiheit (U3/U6) also have four tracks, while Implerstraße (U3/U6), Max-Weber-Platz (U4/U5) and Kolumbusplatz (U1/U2) have three: one with a side platform for outbound trains and two with a shared island platform for inbound trains. Olympiazentrum, Fröttmaning and Kieferngarten also have four tracks each, due to the proximity of the Olympic Stadium, the Allianz Arena football stadium, and the technical base, respectively. At Hauptbahnhof, there is a second U-Bahn station for lines U4/5 at a higher level, giving a total of six U-Bahn tracks.