U6 is a 19.9 km (12.4 mi) long rapid transit line on the Berlin U-Bahn with 29 stations. It runs in a north-south direction [trunk line] from the Berlin locality of Tegel in the north via Friedrichstraße to Mariendorf, a locality in the southern part of the city. It is one of the five large profile (Großprofil) lines. During the Cold War, both U6 termini were in the former West Berlin but the line passed under East Berlin for a short section of its route. Five of its stations were sealed off by East German authorities and the trains went through these so-called “ghost stations” without stopping, while a sixth, Friedrichstraße, remained open primarily as a transfer station between the U6 & the S-Bahn lines using the north-south S-Bahn tunnel, but also as an official border crossing between East & West Berlin. It was formerly named "CI" from 1923 to 1928. Current routing U6 begins its journey from its northern terminus in central Tegel, first running in a southeasterly direction underground along the path of Berliner Straße to the Borsigwerke station, after which it surfaces to run on an embankment beside Seidelstraße & Scharnweberstraße. Just after the Scharnweberstraße station it enters a tunnel & continues under Müllerstraße (which becomes Chausseestraße and then Friedrichstraße). From this point it runs in a distinctly southerly direction. After Mehringplatz at the Hallesches Tor station, U6 crosses under the Landwehr Canal & swings slightly westwards to run parallel to Mehringdamm, which changes its name to Tempelhofer Damm at the Platz der Luftbrücke station, and then to Mariendorfer Damm after crossing the Teltow Canal. U6 crosses this canal in a conduit attached to & immediately below the road-traffic bridge. The line ends at the intersection of Reisseckstraße, Friedenstraße & Mariendorfer Damm at its terminus, the Alt-Mariendorf station. The current rolling stock is BVG Classes F [a 2 consists train] & H [an open gangway car, the entire set]. A six car train. Frequencies The line run every 2-5 minutes on rush-hours, 5 minutes on middays, late evening & after dark every 10-15 minutes & weekends every 2-10 minutes. For more info, go to... https://wikipedia.org/wiki/U6_(Berlin_U-Bahn) https://wikipedia.org/wiki/BVG_Class_F https://wikipedia.org/wiki/BVG_Class_H https://bvg.de/en/connections/route-overview/u6 An F79 train at Zoologischer Garten on the U9 A Class H train on the U5 at Biesdorf-Süd station Friedrichstraße, one of the stations on the U6 The U6 map
