Switzerland has the longest and deepest tunnel in the world

It’s only the biggest (or the longest or the deepest) until someone builds an even bigger one. This is true for so many things, the biggest Ferris wheel, the longest suspension bridge, the tallest building, and the list goes on. For now, Switzerland lays claim to the longest and deepest railway tunnel in the world, the Gotthard Base Tunnel.

For thousands of years the longest tunnel in the world was an ancient Roman tunnel they built to drain a lake. The tunnels are called the Claudius tunnels (after the Roman emperor) and stretch for 6 kilometers or 3.5 miles. Not every ambitious tunnel that begins is finished. A precursor to the Channel Tunnel (aka Chunnel) began construction in 1880 before the British government shut it down for safety reasons.

The Gotthard base tunnel – the longest in the world

The Gotthard Base Tunnel is a twin tunnel that feeds a high-speed rail link under the Swiss Alps to connect northern and southern Europe. The tunnel is about 57 km or 35 miles long and was to take about 1 million trucks off the road so that cargo could be brought in by train instead.

  • Length: 57 km or 35 miles
  • Depth: Up to 2.3 km or 1.4 miles below the mountains
  • Type: railway tunnel
  • Rail type: High-speed rail trains and heavy freight trains
  • Finished: In 2016

Previously, the longest railway tunnel in the world was the 53.9 km Siekan railway tunnel in Japan, followed by the famous Channel (at 50.5 km) under the English Channel.

It is also the deepest tunnel in the world and descends approximately 2.3 km below the surface of the mountains towering above. Another dimension of the tunnel is temperature. The rock can reach a toasty temperature of 46C or 115F.

The rock the tunnel dug through varied from as hard as granite to as soft as sugar. In total, some 28 million tons of rock were excavated.

The longest tunnel under construction is the Mont d’Ambin base tunnel between Italy and France with an expected completion date of 2029. When completed, it is expected to be 57.5 km or 37.7 long and will claim the title of longest tunnel in the world. .


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The Swiss Alps and the need for a massive tunnel

The Gotthard base tunnel is the third tunnel built under the Gotthard, after the Gotthard tunnel and the Gotthard road tunnel. It is considered a base tunnel because it bypasses much of the existing Gotthard railway line (which is a winding mountain road opened in 1882).

The Alps, while stunning, are also a major obstacle to transport in Europe – especially freight. The tunnel not only removed countless lorries from the roads of the Alps, but also significantly reduced the risk of fatal road accidents and environmental damage posed by heavy goods vehicles.

  • Reduced: The tunnel has reduced travel time, environmental damage and road accidents
  • Cost: The project cost more than $12 billion
  • Referendum: The tunnel was approved in a Swiss referendum in 1992

As Switzerland is famous for its open source democracy, it had to be approved by referendum in 1992. It was approved by 64% of Swiss voters and the first preparatory work began in 1996 with official construction starting in 1999.

Related: Are There Really Tunnels Under New York? That’s what we know

Use the tunnel today

The tunnel has better connected the canton of Ticino south of the Alps with the rest of Switzerland (which lies mainly north of the Alps). A trip from Basel in Switzerland to Milan in Italy cut the travel time by about an hour.

  • How to go through the tunnel: Book a train through the Swiss Alps
  • Prime: Traveling by high-speed train

If you want to go through the tunnel, remember that it is a train-only tunnel. You will need to book a ticket from northern Switzerland (like Basel or Zurich) to southern Switzerland (like Lugano) or Italy (like Milan).

There are more frequent and more convenient services with new and upgraded rolling stock which has made the journey for passengers through the tunnel more attractive. Railway upgrades to the tunnel gradually came into being between around 2016 and 2020 as authorities sought to make this tunnel the main route.

Today, the tunnel stands alongside the Panama Canal and the Channel Tunnel as one of the greatest engineering feats of modern times.

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