The so-called "city tunnel" passes under the track field of Zurich's main railway station and will connect districts 4 and 5 as a bicycle tunnel from 2024. There will also be a connection to the bicycle station at Europaplatz as well as to Sihlquai and Konradstrasse. A great project for cyclists in Zurich, which above all means more safety while making cycling in the city centre more attractive. Numerous construction measures will be required before the tunnel is ready to open.

The tunnel ramp for the new bicycle subway will be built in the area of the (former) "Sihlquai main station" stop - and this is exactly where the control unit for the traffic light system is located. Before the ramp can be built, the control unit must therefore be moved to a new location.

cablex has been commissioned by the Traffic Department of the City of Zurich to ensure the maintenance, renovation and expansion of the so-called coordination lines between traffic signal systems and the traffic computer. The coordination line is part of the communication network. It forwards the command of the traffic computer to the corresponding control unit.

In connection with the relocation of the control unit, the existing coordination cables and sleeves (50x4x0.6/10x4x0.6) must also be relocated. As the cables in this section handle the communication of many traffic light systems, it was necessary to make some preparations in advance. The challenge here is therefore to reroute the signals to other cables first of all and then set up a bypass circuit. After all, the traffic and pedestrian lights as well as other light signal systems should also function during the reconstruction activities and ensure road safety. Only once this has been ensured can the control unit and cables be moved to their new location.

The switchover at the main station/Sihlquai junction was the most extensive one to date for the "Traffic" infrastructure unit. It involves a great deal of responsibility for road safety in the vicinity of the Zurich railway station.

During the switchover, the team with project manager Stefan Kümin works with with a great deal of concentration and precision. Each of the 240 wires connected to the signalling equipment and the control element is tested before the sleeve is sealed to ensure safe operation.

On this day, however, it's not just about keeping a cool head in the hustle and bustle of the construction site. While pulling the cable, the men impressively show why they no longer need to visit a gym after work, and why they have more than earned a large portion of "rösti with egg and cervelat" for lunch.