The two bores of the Saverne Tunnel were excavated with a , tunnel boring machine (TBM), manufactured by Herrenknecht. The TBM was used to excavate of the tunnel, the remainder consisting of false tunnel constructed at both ends. The TBM was christened Charlotte—in honor of a girl from a nearby village—in a ceremony on 25 October 2011. It began excavation of the first bore on 10 November 2011 from the eastern side of Mont Saint-Michel and completed the first bore over a month ahead of schedule on 19 June 2012. For the first bore, 1932 rings were installed, using 15,456 precast concrete lining segments (8 per ring). The TBM excavated of earth at an average speed of per day.