Possibly because of French finance the construction of the Mountain Route the 58 km Frutigen-Brig line, was assigned to a French construction consortium, the major civil engineering work on the section being single-track Lötschberg Tunnel. Construction began on 15 October 1906 but within months the Swiss federal authorities ordered the BLS to enlarge the tunnel to double track and to profile its access ramps to suit. Money was not forthcoming for the provision of a double track line throughout and only the Lötschberg Tunnel itself was constructed in this way. Due to an accident on 24 July 1908 in which rock, washed with alpine waters, collapsed into the tunnel gallery killing 25 Italian miners, construction work was halted for six months before the gallery was sealed and plans made to bypass the site. The plan was to construct three curves inside the mountain and extending the length of the tunnel to . The breakthrough was finally made on 31 March 1911.