The Gotthard Base Tunnel in Switzerland is a 57km line under the Swiss Alps between northern and southern Europe and as well as being longer than any other tunnel in the world, it's also deeper. Goods that were being transported on the route by a million lorries per year will now go by train.
Sadly, its construction has meant the demotion of the 50.5km Channel Tunnel linking the UK and France into third place in the rankings of the world's longest tunnels. Japan's Seikan rail tunnel has been pushed down into second at 53.9km.
From Sunday 11 December passengers will now be able to race under the Alps in as little as 17 minutes. For those travelling between Zurich and Milan on the route, the journey time will be slashed by an hour to two hours and 40 minutes.
The initial inauguration of the Gotthard Base Tunnel was back in June following a lengthy 17-year pioneering project, but it'll really shake up the nation's transport system from this weekend now the Swiss Federal Railways (SBB) has finished safety and technical tests.
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The tunnel will create a mainline rail connection between Rotterdam, Netherlands and Genoa in Italy. Some 50 passenger trains will pass through the Gotthard Base Tunnel daily along with 160 cargo trains. The forecast is for Gotthard traffic to shoot up from 9,000 passengers a daily in 2015 to 15,000 by 2021 - an increase of 67 per cent, and reach 18,000 by 2025.
It has been financed by value-added and fuel taxes, as well as road charges on heavy vehicles and state loans due to be repaid in a decade.