The Saverne Tunnel (), also known as the Ernolsheim-lès-Saverne Tunnel (), is a twin-bore , high-speed rail tunnel in western Bas-Rhin, France. It carries the LGV Est line of France's TGV high-speed rail network through the narrowest part of the Vosges mountain range, beneath Mont Saint-Michel and adjacent to the Saverne Pass. The tunnel consists of two bores, containing one rail track each, that are connected by passageways every . The LGV Est crosses the Haspelbaechel viaduct near the western end of the tunnel. The tunnel was excavated by a tunnel boring machine between November 2011 and February 2013. Civil engineering work on the tunnel ended in April 2014 and it opened with the rest of the second phase of the LGV Est on 3 July 2016. The total cost of the tunnel was approximately €200 million.