With the construction of the Berlin Wall on August 13, 1961, the city was divided, and with it the subway and commuter rail networks. However, two U-Bahn lines and one S-Bahn line crossed under the eastern sector, their starting and destination stations were in West Berlin. The trains did not stop at stations in East Berlin. The underground stations were closed and became "ghost stations": Trains moved slowly through deserted stations guarded by GDR armed guards. The exception was Friedrichstrasse station with its checkpoint.
In East Berlin, the stations of the West lines largely disappeared from the cityscape. Underground and S-Bahn signs were removed, entrances walled up. Over the years, an underground barrier system was created. Despite this, people still tried to escape through the railway tunnels, but only a few succeeded. After the fall of the Wall, the underground barriers were dismantled and the transport system reunited.
The exhibition on the mezzanine floor of the former "ghost station" Nordbahnhof uses multimedia to explain this aspect of the history of division with numerous case studies. Part of the exhibition, which can be seen during the operating hours of the S-Bahn, are also the markings of the former barrier walls of the station. The exhibition "Border Stations and Ghost Stations in Divided Berlin" is the first part of the permanent exhibition in the outdoor area of the Berlin Wall Memorial that will be created by 2012. The expansion will make the memorial a central place of remembrance for the division of Germany and the Berlin Wall.