German railways are using a new system that allows tunnels to be widened while keeping the trains running through. Herrenknecht, better know for its tunnel boring machines, has developed a tunnel widening system (TES) to enable railway lines to be electrified. In the second half of the 19th and early 20th centuries, hundreds of railway tunnels were built in Europe. They are largely still in operation today. In the coming decades, a many are due for renewal. The Herrenknecht Tunnel Enlargement System (TES) offers a solution for widening the profile of old railway tunnels while rail traffic continues to run.
Two TES machines from Herrenknecht have been in use since January 2024 for the renewal of 160-year-old Deutsche Bahn (German Railways) tunnels near Limburg an der Lahn. The tunnels are being renovated while rail service continues. The 426-metre long Fachingen tunnel and the 732-meter long Cramberg tunnel are part of the Lahn Valley Railway connecting the cities of Koblenz and Wetzlar.