Horchheimer Tunnel, Koblenz

It was “three cheers” in the Horchheimer Tunnel in Koblenz in June 2021, when DB Netz AG awarded the contract for the renovation of the Horchheimer railway tunnel to PORR in consortium with FELDHAUS Bergbau GmbH & Co. KG and Heinz Schnorpfeil Bau GmbH. The contract incorporated the entire tunnel renovation process, from the necessary demolition works to the new tunnel construction, manufacture of the facilities for surface and underground dewatering, cable works and cable laying, restoration of the superstructure and track system and associated civil engineering works.

The 582m-long Horchheimer Tunnel was first opened to rail traffic in 1902. The single-track railway between the Koblenz Pfaffendorf and Koblenz Horchheimer Brücke branches has run through the tunnel ever since. Environmental factors such as mountain water finally meant that after 115 years in operation, the tunnel reached the end of its working life. As a result, a complete refurbishment was called for.

In the process, the Horchheimer Tunnel is being furnished with a new concrete base to protect against the pressure of mountain water. The old brickwork and the cliff face itself are being broken away in sections. Owing to the overroofing of the tunnel (expansion of the space above the tunnel roof), both tunnel entrances and the retaining wall to the south need to be demolished and reconstructed.

A focus on the environment and nature conservation

The employer emphasised the importance of environmental protection and nature conservation in the context of the project. Where the planned construction works cannot avoid impacting the natural environment, compensatory works are to be carried out. In the early stages, precautions were taken to protect the lizards of the area. Works designed to protect local bat populations were also undertaken before the main project got underway.