Some 13 years after work started on the Lötschberg project in Switzerland, client BLS AlpTransit last month opened the rail tunnel to commercial service as the longest in the country and third longest in the world. The construction challenge of the project involved a significant portion (18.7km) of TBM boring but the majority of the excavation (about 46km) between Frutigen and Raron was undertaken by drill and blast. The TBM drives were 9.4m diameter and the drill and blast stretches have sections of 65m2. Construction of the tunnel, almost 35km between portals, was undertaken from both ends and three intermediate shafts. Geology along the route varied from flysch, sandstone, marly limestone and slate in the northern side to granite in the middle and then gneiss, schists, amphibolites and sediments to the south end. To launch the project, a 5m diameter TBM bored a 9.6km long exploratory tunnel at the north end, and which was incorporated as a safety tunnel. For the official inauguration, a RE 465 loco set of the firework celebrations at the north portal.
Celebrations at the opening of the Lotschberg tunnel Lotschberg Tunnel
