4th Elbe Tunnel

Hamburg, Germany

Project

Construction of a fourth tunnel (3.325 km long) under the River Elbe.

The largest tunnel boring machine in the world, christened TRUDE (Tief Runter Unter Die Elbe - Deep Down Beneath The Elbe), was used for the project, measuring 14.2 m in diameter.

The external tunnel wall consists of a 2 m-wide and 70 cm-thick reinforced concrete tubbing.

The tunnel lies 27 m below the water surface at its deepest point.

The fourth tunnel was opened on 27 October 2002.