Limburg an der Lahn

Fachinger Tunnel

Refurbishment of a historic railway tunnel whilst rail services continue to operate

Built between 1861 and 1862, the structure is one of the historic railway tunnels on the Lahn Valley Railway. The well-known route connects Wetzlar and Koblenz and is considered particularly scenic due to its route along the River Lahn. As a long-term closure of this rail link – which is vital for commuters and tourists – was out of the question, PORR, in a joint venture with FELDHAUS Bergbau GmbH & Co. KG and Heinz Schnorpfeil Bau GmbH, carried out the construction work whilst services continued to run.

A sustainable refurbishment for the Fachinger Tunnel

As part of the project, the existing tunnel cross-section was widened to permanently ensure the required clearance gauge. The scope of works included the complete refurbishment of the tunnel structure with a new in-situ concrete inner lining, including portal structures and side paths. In addition, the superstructure was renewed, retaining walls were constructed, embankments and slopes were stabilised, and a culvert was replaced. This was supplemented by extensive underground cable works, cable laying and signalling works to modernise the infrastructure.

Particular attention was paid to protecting the sensitive surrounding environment. The construction site was located within Protection Zone III of the ‘Staatlich Fachingen’ mineral spring protection area. In addition, measures for water and soil protection were implemented, and regular environmental monitoring of the construction work was carried out. Once the works are complete, the construction site will be recultivated and restored to its original condition.

Tunnel renewal whilst traffic continues

The modernisation was carried out using the ‘tunnel-in-tunnel’ method with a specially developed tunnel-widening system. This method enabled the existing tunnel cross-section to be enlarged whilst rail operations were largely maintained. To this end, a temporary track was positioned in the centre of the tunnel and operated within a protective enclosure. This meant that train services could be safely maintained during the construction work, whilst the structure was adapted to meet current operational and safety requirements.

The team faced additional challenges due to the confined space, the restricted accessibility of the construction site and the fact that logistics were predominantly track-bound. A key project milestone was the second total closure in spring 2026 to complete the final double-track configuration. The modernised tunnel was commissioned on 15 May 2026.