World's longest tunnel completed in Switzerland will save an hour on journey times

Journalists walk at a multifunction and emergency stop station of the NEAT Gotthard Base Tunnel during a media visit near the town of Sedrun August 24, 2015. Crossing the Alps, the world's longest train tunnel should become operational at the end of 2016, consisting of two parallel single track tunnels, each of a length of 57 km (35 miles). (Reuters)

Swiss builders have completed construction of the world’s longest tunnel through a mountain in the south of the country.

The 35-mile NEAT Gotthard Base Tunnel will make rail connections between Zurich, Milan and Turin easier, shortening travel times about about an hour.

The structure cuts through the base of mountains in the Gotthard region, an important north-south corridor between Switzerland and the northern Italian plain.

Trains will be able to run through it at 150 mph (241kmph) thanks to its nearly flat gradient. The structure actually consists of two separate single-track tunnels so trains can run in either direction.

The new tunnel steals the longest tunnel crown from Japan's 14.5-mile Seikan Tunnel.

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The first passenger trains are expected to run through the structure in June 2016 after it has been fully outfitted and tested.

The tunnel cost about £6bn and was entirely funded by the Swiss authorities.