World?s largest tunnel boring machine accepted by the customers. The Herrenknecht Mega TBM will excavate a road tunnel in Madrid.

June 17, 2005. The Herrenknecht EPB Shield S-300 is the world?s largest TBM with truly unique features in terms of engineering. To master the world?s largest excavation diameter in challenging ground conditions, Herrenknecht engineers developed a so far unique cutting wheel concept especially for this project. It consists of a 7m-diameter central cutting wheel and an outer cutting wheel, located on the same level, with a maximum excavation diameter of 15.20m.