Riding a train beneath the Alps: the great tunnels that achieved this feat

From Fréjus to the still under-construction Brenner tunnel, the incredible story of trains running beneath the Alps.

It was 1871. Italy was experiencing its Third War of Independence, in Paris, a popular uprising led to the establishment of the “Commune” with socialist inspiration, Antonio Meucci was experimenting with the first prototype of the electric telephone, and under the Alps, the railway tunnel of Mont Cenis was inaugurated.

If it’s true that the 19th century was the century of railways, it’s equally true that the search for increasingly faster and more accessible solutions for crossing the Alps is a need rooted in human history, dating back to 218 BC when Hannibal and his army marched on Rome from Spain, crossing – according to historians – the Isère valley and reaching Mont Cenis and the Little Saint Bernard Pass. Even then, well over two thousand years ago, the key passage was from France to Italy (then Gaul and Rome), which would remain the two ends of a route traversed by millions of people and vehicles, connecting Italy to the rest of Europe.

Not surprisingly, the Fréjus tunnel, opened on September 17, 1871, is not only one of the most colossal infrastructural works of the 19th century but also a pioneer for the many road and railway tunnels that have connected Italy to France since then, further strengthening the already strong human and commercial relations between the two countries.

35 hours from Paris to Turin: the world before the train

In European history, there is a before and after marked by the construction of the Fréjus tunnel. In the mid-19th century, before the Modane to Bardonecchia railway was put into operation, traveling from France to Italy was a true adventure. The train only reached the foothills of the Alps, where travelers had to continue their journey on a stagecoach that reached an altitude of two thousand meters at the Moncenisio Pass. Decades earlier, Napoleon had constructed that road, which, once the pass was reached, descended into Italy toward Susa, where passengers could catch a train to Turin.

The construction of the Fréjus tunnel began in 1857, conducted in parallel on both sides of the border, the French and the Italian. According to historical reconstructions, about 4,000 workers participated in the excavation, working exhausting shifts of up to 14 hours a day. The construction activity in the area also contributed to a profound transformation of the local economies, starting with Bardonecchia in Italy, which evolved from a shepherd’s village into one of the most technologically advanced areas on the Peninsula. After years of work, on December 25, 1870, the last wall fell, and the two tunnels joined with only a few centimeters of difference, marking the final phase of the operation. Despite its inauguration on September 17, 1871, the first London-Brindisitrain passed through the tunnel on January 5, 1872. In 1980, over a century later, the Fréjus road tunnel was opened next to the railway tunnel, and together they represent a strategic infrastructure for connecting the two countries. The railway, inaugurated during the time of the Kingdom of Italy, now hosts high-speed trains that can connect Milan to Paris in just a few hours.

San Gotthard: the world's deepest railway tunnel

At some points, the height of the mountain above the travelers’ heads reaches 2,300 meters. This is one of the records of the San Gotthard tunnel, an undertaking conceived in 1947 and first planned in 1962 with the goal of connecting Italy to Switzerland beneath one of the most challenging passes in the Alps.

The Webuild Group was also involved in this project, responsible for constructing the Bodio and Faido sections, each 30 kilometers long, forming part of an underground network of tunnels that totals 152 kilometers. The San Gotthard railway tunnel is indeed a unique work, opened for train traffic on December 11, 2016, capable of connecting Zurich to Milan in less than three hours, reducing travel times by about an hour. Currently, in addition to its depth record, it also holds the record for length, with its 57 kilometersof tunnel. However, this record will soon be surpassed by another colossal project, this time aimed at connecting Italy to Austria.

Brenner: the tunnel that breaks the world record

The record held for years by the San Gotthard is about to be surpassed by another major European project, primarily designed to overcome the natural obstacle of the Alps. Once completed, the Brenner Base Tunnel will connect the Italian town of Fortezza to Innsbruck in Austria, covering a total length of 67 kilometers beneath the mountains and making a crucial addition to the completion of the Trans-European Transport Network (TEN-T) corridor between Munich and Verona.

The Webuild Group is also contributing to this project and is working on various sections with innovative technologies such as ground freezing, a technique that stabilizes and secures the ground during excavation by using liquid nitrogen. The ultimate goal in this case, too, is to decongest the highways by providing a faster and less polluting means of transportation. This is a complex endeavor because the construction sites are often located in inaccessible territories, and the tunnels run through a variety of terrains, as was the case with the construction of the Isarco River Underpass on the Italian side of the project.

This effort will yield results, as travel times between Fortezza and Innsbruck will be reduced from 80 to 25 minutes, a 69% reduction. Bringing us back to today, it will be a bit like transitioning from the stagecoach to the train once again.