

A visitor stands at the Erstfeld-Amsteg section of the Gotthard Base Tunnel Oct. 5. With a length of 35 miles crossing the Alps, the world's longest train tunnel should become operational at the end of 2017. Arnd Wiegmann/Reuters
The tunnel drilling machine 'Sissi' breaks through the last section of the Gotthard Base Tunnel near Sedrun in the canton of Grisons, Switzerland, on Oct. 15. Arno Balzarini/Keystone/AP
Swiss Minister of Environment, Transport, Energy and Communications Moritz Leuenberger (c.) and miners celebrate after the drill machine 'Sissi' broke through the rock at the final section Faido-Sedrun, at the construction site of the Gotthard Base Tunnel, on Oct. 15. Christian Hartmann/AP
A miner stands in front of the drill machine 'Sissi' after it broke through the rock at the final section Faido-Sedrun, at the construction site of the Gotthard Base Tunnel, on Oct. 15. Christian Hartmann/AP
An elderly man watches as drill machine 'Sissi' breaks through the rock at the final section Faido-Sedrun, in an electronics store in Bern, Switzerland, on Oct. 15. Michael Buholzer/Reuters
Miners wave a Swiss national flag (l.) and a flag of the Graubuenden canton (r.) as they celebrate after 'Sissi' broke through the rock at the final section of the tunnel, on Oct. 15. Christian Hartmann/AP
A small chapel in memory of the eight miners killed during the construction of the tunnel hangs at a wall of the Gotthard Base Tunnel near Sedrun in the canton of Grisons, Switzerland, on Oct. 15. Arno Balzarini/Keystone/AP
Swiss Minister of Environment, Transport, Energy and Communications Moritz Leuenberger (l.) makes a speech before the drill machine 'Sissi' commences to break through the rock at the final section of the tunnel, on Oct. 15. Christian Hartmann/Reuters
Miners watch as the drill machine works at the construction site of the Gotthard Base Tunnel on Oct. 15. The world's longest train tunnel should become operational at the end of 2017. Christian Hartmann/AP
This Aug. 27 photo shows a worker taking a break in the shaft of the gate, still to be built, at the track change between the two tunnels in the Gotthard Base Tunnel's 'Faido' section near Faido in the canton of Ticino, Switzerland. Martin Ruetschi/Keystone/AP
This May 29, 2009, photo shows the entrance to the 'Erstfeld' north portal of the Gotthard Base Tunnel (background) and a conveyor belt for the excavated material (front), near Erstfeld in the canton of Uri, Switzerland. Gaetan Bally/Keystone/AP/File