North-south light rail Cologne

Sophisticated subway construction under the historic old town

The North-South light rail Cologne is currently one of Germany's largest urban development projects and at the same time one of the largest archaeological excavation sites in a European metropolis. The largest part of this approximately four-kilometer-long route runs underground in two single-track, parallel tunnel tubes. Only 270 meters of the track are built above ground. The underground section includes the seven stops Breslauer Platz, Rathaus, Heumarkt, Severinstraße, Kartäuserhof, Chlodwigplatz and Bonner Wall. The Kölner Verkehrs-Betriebe AG (KVB) and the Studiengesellschaft für Tunnel und Verkehrsanlagen mbH (STUVAtec) have shown how modern fire protection can look like in such plants in the Nord-Süd Stadtbahn in Cologne in close and constructive cooperation.
Underground special conditions prevail: Fire and fire gases, following the thermals, go upwards, exactly in the direction in which endangered people have to flee. Retractable smoke curtains, which are mounted concealed and drive only in case of fire to their destination position, provide good protection for people fleeing. Such smoke curtains usually require lateral guide rails to minimize the design-related leakage areas. Since the arrangement of pillars with integrated guide rails was not possible in all places, a solution had to be found, to form the gap of two abutting smoke curtains as small as possible. This was achieved in close cooperation with the manufacturer by optimizing the smoke hood boxes in order to be able to guide the smoke blanket cloths close enough together. In addition, with a newly developed hinge for this purpose a connection of adjacent ballast rails was made possible. This hinge allows a slight movement of the two connected smoke curtains in the vertical and horizontal directions to compensate for possible asynchronisms during extension. At the same time, it prevents the adjacent smoke curtains from being able to diverge.