Unter den Linden above and behind the tracks
A decisive step for the completion of the underground station Unter den Linden is the special design of the track area. Elaborate substructures are required for the slab above the track and for the rear track wall so that they can withstand the loads of an approaching and departing underground railway.
For the slab above the tracks, a technique was used that originally came from church construction: the Rabitz slab. This is necessary because the ceiling can only be plastered due to its curvature. In order for this to happen, an elaborate steel substructure was first mounted overhead on the ceiling. A total of 146 tons of lime-cement plaster were then applied to 2080m² of ceiling. This mineral mixture fits in well with the overall concept of the natural materials used at the Unter den Linden underground station.
Now the rectangular lamps above the track have to be installed in the ceiling and of course the corresponding cables have to be connected so that the platform edge is sufficiently illuminated for the passage of the new U5.
For the steel substructure of the rear track wall, steel girders with a total weight of 340 tons had to be brought into the structure. A total of 3,600 running metres of supporting profiles were then installed. Afterwards, 530m² of aluminium panels were and will be installed. As soon as this has been completed, everything is ready for the content design of the rear track wall in cooperation with the Humboldt University.