Ten years ago this month, construction finished on one of the most impressive feats of engineering in the world. The Gotthard Base Tunnel, a railway tunnel below the Lepontine Alps in Switzerland, is the longest and deepest transport tunnel in the world. It opened in June 2016 and has provided a high-speed rail link between northern and southern Europe, specifically running between Rotterdam in the Netherlands and Genoa in Italy.
Engineering Marvel Beneath the Alps
Called a Base Tunnel because it travels through the base of the mountain rather than snaking over the ranges, the journey is largely straight and flat. High-speed trains can reach 250 km/h, significantly slashing travel times. Construction took 17 years of continuous labour and cost approximately CHF 12.2 billion (£11.2 billion). Engineers and construction crews excavated more than 28 million tonnes of rock using massive boring machines and blasting to clear the way.
Deepest and Longest in the World
At 57 km long, the tunnel is the longest in the world. Its deepest point lies 7,546 feet below the surface, making it the deepest transport tunnel as well. Before its construction, trains had to traverse winding mountain routes, limiting speed and cargo capacity. Now, trains whip through solid rock between Erstfeld in the north and Bodio in the south in just 20 minutes.
Impact on Travel and Passenger Numbers
Since its opening, the tunnel has carried thousands of people. According to the Swiss Federal Railways, the average number of passengers travelling through the Gotthard by train almost doubled in 10 years, reaching 16,400 per day in 2025 compared with 9,000 per day in 2015. This incredible feat of engineering continues to transform transalpine rail travel.
