The two deepest transport tunnels in the world are both in the Alps: the Mont Blanc road tunnel between France and Italy, and the Gotthard Base rail tunnel in Switzerland. As the former closes for 15 weeks, the latter has fully reopened after a year of total or partial closure.
The Mont Blanc road tunnel is in its 60th year of operation, connecting Paris and Geneva with Milan and Turin. But the seven-mile short-cut between Chamonix and Courmayeur needs attention. The Alpine underpass closed at 5pm on Monday 2 September for “deep renovation works”. The Mont Blanc tunnel is due to reopen after 15 weeks, at 5pm on Monday 16 December – in time for the start of the main ski season.
The work involves the “complete reconstruction of two portions of the tunnel vault of 300 metres each, making it one of the first major European tunnels to undertake deep renovation works on its structure”.
Both the recommended diversions have drawbacks. Using the Frejus tunnel to the southwest increases the distance between Geneva and Milan by around 100 miles The Grand-Saint-Bernard tunnel to the northeast adds only 50 miles, but involves a more challenging drive.
In contrast, the Gotthard Base tunnel through the heart of Switzerland is now back to full operation – cutting many train journeys from Zurich to Como and deeper into Italy by an hour. The term “base tunnel” refers to a link through the base of a mountain pass.
The 35-mile subterranean express route is the longest and deepest rail tunnel in the world – at one point more than 8,000 feet deep.
The Gotthard Base tunnel opened to rail traffic in 2016, but in August 2023 a freight train derailed. No one was hurt.
The twin-tube timesaver was closed completely initially. It later partially reopened with a single bore operation, but is now fully functioning.
EuroCity trains take only 2 hours and 22 minutes between Zurich in the north of Switzerland and Chiasso, the southernmost station. Milan is 55 minutes further.