Rising as it does in high curves over the tracks, the roof has always been the distinguishing feature of a railway station's architecture. Anhalter Bahnhof, which opened in Berlin in 1880, is no exception and had, at its time, the largest station hall with no supports - 167.79 metres long, 60.72 metres wide and 34.25 metres high.

The glass roof of the new Berlin Hauptbahnhof is a high-tech construction of the modern age. The east-west roof of the station that covers the new Stadtbahn bridges was designed using advanced CAD and material processing techniques. A total of 23 steel roof trusses support an arch 16 metres high and 59 to 68 metres wide. Because the hall is situated in a curve and widens towards the centre of the station building, no one glass pane in the roof resembles the others. No less than 85 kilometres of steel cable hold the roof secure in wind and weather.

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The roof was built in a record time of just four months. Before all 10,000 seams could be welded and all the cables pulled taught, the roof trusses, weighing 40 to 50 tons each, had to be supported by scaffolding weighing a total of 3,600 tons.

The old Lehrter Stadtbahnhof had to be removed

The construction of the roof was the "eye of the needle" in the completion of the entire station. The old Lehrter Stadtbahnhof had to be removed to enable construction to continue underground. But before this was possible, it was necessary to have the trains already in operation on the new Stadtbahn bridges. That required not only having the main work finished on the east-west roof, but the tracks in the station hall also had to be equipped with the necessary technical installations and the S-Bahn platform to be almost completely fitted out.

In June 2002, all the preparation work required to put the east-west bridges into operation under the new roof had been completed. Between 16 June and 4 July 2002, the new bridges went into operation in two stages. Initially, long-distance and regional services between Berlin Zoologischer Garten and Berlin Ostbahnhof were interrupted for five days. During this time, the two long-distance tracks of the Berlin Stadtbahn (section through the City) were connected to the new bridges.

On 21 June 2002, the first scheduled train ran through the east-west platform hall of Berlin Hauptbahnhof. After that, S-Bahn services were interrupted again for 12 days.

In addition to work on tracks, contact rails and signalling technology, extensive work still had to be carried out on the bridges. The first train stopped in the new station on 4 July 2002, when S-Bahn services resumed.

Photovoltaics

On the south side of the east-west hall roof, a photovoltaic system has been in operation since July 2003. On an area covering 1,700 square metres, 780 solar modules with 78,000 transparent, high-performance solar cells have been integrated into the glass panes. Like the glass panes, each of the solar modules is of a different size. The individual surface areas of the cells are between 1.7 and 2.6 square metres and have a total power output of 190 kilowatts. The solar cell system generates an average of 160,000 kilowatt hours every year, which accounts for almost two percent of the power consumption of Berlin Hauptbahnhof.