The S1 was created along with the
S2 and
S3 on 9 January 1984, when the
Berliner Verkehrsbetriebe (BVG) took over the S-Bahn network from the East German
Deutsche Reichsbahn in
West Berlin: however, the dilapidated state of the West Berlin network at the time meant that the first S1 trains did not run until 1 May 1985, when the line between Wannsee and Anhalter Bahnhof reopened. In 1990, the S1 was extended to Frohnau, while the S2 was curtailed to
Gesundbrunnen. It was extended to its present northern terminus of Oranienburg on 31 May 1992, after the reopening of the Berlin Northern Railway between Frohnau and . ==References==