Lotschberg Base Tunnel, built through the Alps in Switzerland, is the third longest railway tunnel in the world. The 34.6km long tunnel allows passenger and freight trains operated by BLS on the Lotschberg line. The tunnel includes a non ballasted track on which trains run at 250kmph.The tunnel construction began in April 2005 and was completed in 2006. It was opened for full scale operations in December 2007. Around 20% of the tunnel was constructed by using tunnel boring machines, and the rest through conventional blasting techniques. Excavated material in the tunnel amounted to 16 million tonnes.The tunnel was designed with twin single track tubes, but it was only half finished as only one of the tubes was fully equipped, while the second tube was left largely as a shell. The two tubes are interconnected by transverse tunnels at 333m intervals.