Swiss effectively disappear Alps: World's largest tunnel opens

Tunnel nerds, rejoice. The Swiss are today celebrating the opening of the world's largest underground passage to mark its completion 17 years after construction began.

The €12bn (£8.5bn) Gotthard base tunnel is 57km (35 miles) long and will overtake Japan's 53.85km Seikan railway tunnel to become the world's largest and deepest underground passage. The Channel Tunnel is the third largest at 50.5km.

The completed tunnel travels up to 2.3km below the surface of the mountains above and through rock that reaches temperatures of 46˚C without ventilation due to a high lithostatic pressure from rock above it – which can measure up to 2,500m in some sections*.

It will create a mainline rail connection between Rotterdam in the Netherlands and Genoa in Italy, get trucks off the road and reduce travel time between Milan and Zurich from 3 hours and 40 minutes to two hours and 40 minutes.

The Swiss are justifiably proud of the engineering achievement and are inviting "guests of honour" from Switzerland and abroad to the opening event and welcome the entire population for "an unforgettable public festival."

Federal transport office director Peter Fueglistaler told Reuters the tunnel was "a masterpiece of timing, cost and policy."

"For us, conquering the Alps is like the Dutch exploring the oceans," said Fueglistaler.

Engineers had to remove 73 kinds of rock ranging in texture from granite to sand. According to Reuters, nine workers died in the process.

This morning a Catholic priest, a pastor, a rabbi and an imam were present for the ceremony, according to Swiss Info.

This coming weekend – June 4 and 5 2016 – between 50,000 to 100,000 visitors will be offered a unique programme at the festival sites on either end of the 57km tunnel.

The highlights of the festival: tunnel rides with the Gotthard shuttle train at up to 200kmph, presentations by Swiss artists and an interactive multimedia exhibition on the Gotthard. ®

Bootnote

For those who are interested, the ventilation plan used 24 axial fans, six air locks – thus reducing local airflow needed and managing risks of smoke in the event of a fire – and 16 air barriers. The cooling system includes 30 local air coolers, 130km of cooling pipes, 12 circulation pumps, one pressure exchange system and three cooling towers.