A six-kilometer-long twin-track railway tunnel beneath the River Ruhr, the Port of Duisburg and residential areas, extremely cohesive marl encountered in some sections of the tunnel, fine gravel, silt and a high groundwater level: These are the specific requirements of the Meiderich Ruhr Tunnel, which was planned to cut the travel time between Duisburg Central Station and Meiderich Station from 18 to six minutes.
Two kilometers of the six-kilometer-long section were driven by a Herrenknecht Mixshield. For the first time, Herrenknecht engineers installed a stone crusher infront of the grillbars in the invert segment. The heterogeneous geological conditions and the sections with low overburden beneath the quarter of Meiderich could safely be mastered. Despite the difficult ground conditions and a few initial delays the TBM was ahead of schedule: The Mixshield completed its work one year ahead of schedule.