Berlin Hauptbahnhof fall of the Berlin Wall in 1989, city planners began work on a transport plan for reunified Berlin. One element of this became the "Pilzkonzept" (mushroom concept), in which a new north-south railway line intersecting the Stadtbahn was to be constructed. The name derived from the shape formed by the new line and existing lines, which vaguely resembles a mushroom. In June 1992 the federal government decided that the new station should be built on the site of Lehrter Bahnhof. While close to the centre of Berlin and government buildings, the area was still not heavily populated. The following year,
Berlin-Spandau station was expected to lead to the reopening of the line to Staaken via a new S-Bahn station called "Rathaus Spandau" (rather than Spandau West). However, this was postponed, as U-Bahn line U7 was completed to Rathaus Spandau (located next to Spandau West station) on 1 October 1984. The initial plans for the Hanover–Berlin high-speed railway were developed during the same decade. Negotiations with East Germany for what was initially intended as a transit route between West Germany and West Berlin began in autumn 1988. The fall of the Berlin Wall and the completion of negotiations with an agreement on the