100 kilometers of cable for 2.2 kilometers of tunnel
Since 2020, the Berlin subway line U5 runs 23 kilometers from Hönow in Brandenburg via the government district to the main train station. After the expansion of the last section, the former “Kanzler U-Bahn” U55, which had been running as an isolated solution between the Brandenburg Gate, the Bundestag and the main station since 2009, became part of the second-longest U-Bahn route in Berlin. To close the gap, Bayka supplied telecommunications cables, signal cables and return conductors with a total length of more than 100 kilometers, all of which meet the requirements of the highest CPR reaction to fire class B2ca.
Challenge
The tunnel is 2.2 kilometers long and connects Alexanderplatz with the Brandenburg Gate. Well-known Berlin architectural firms were commissioned to design the four new train stations “Rotes Rathaus”, “Museumsinsel”, “Unter den Linden” and “Brandenburger Tor”. And so each underground station is a sight in itself, representing the historical center of the capital. The most impressive thing is certainly the ultramarine blue starry sky illuminated with 6,000 lights at the stop on “Museumsinsel”, which was the last to open in 2021. In order to offer people and the building structure the greatest possible safety, fire protection was of course the top priority for the Berliner Verkehrsbetriebe BVG. Consistently flame-retardant and halogen-free cable solutions play an important role.
Solution
As a universal cable manufacturer, Bayerische Kabelwerke is able to develop individual solutions for every requirement. In close collaboration with the customer, various types of cables with specific properties were designed and delivered for the subway tunnel. They all have one thing in common: they are flame-retardant, halogen-free and correspond to the highest reaction to fire class B2ca according to CPR. The order included 41 kilometers of telecommunications cable, including 35 km of BayCom® nonfire B2ca OFC TUSI® fiber optic cable with reinforcement, 60 km of A-H(L)HV signal cable and 7 km of (N)HA return current conductors.
