The longest railway tunnel in the world under construction in the Alps

world longest railway tunnel cross the alps, mont cenis
Map image by Openstreetmap.org.

Both France and Italy have started a massive construction project that will produce the longest railway tunnel in the world. The 57.5 km long tunnel is being excavated in the Alps, under Mont Cenis mountain. The railway line from Lyon to Turin dives into the tunnel in the French town of Saint-Jean de Maurice and arrives in Italy in Susa. The new tunnel is scheduled to be ready by 2032.

Two tunnels will be built for passenger and freight trains. Travelers will be able to enjoy fast travel times, for instance, between Paris and Milan: after the new tunnel is open, it is only a four hour journey between these two major cities. The scenery both in France and Italy is pretty, but near the Alpine mountain range, there won’t be much to see from a train seat since most of the time between Lyon and Turin trains will travel in tunnels with the Mont Cenis section being the longest one.

Passenger trains can reach a maximum speed of 220 km/h along the new railway line, and freight convoys up to 100/120 km/h. The third, small tunnel between the two traffic tunnels is built for safety purposes where passengers may be evacuated if required. In addition, three safety shafts along the tunnel are linked to the surface.

With the a budget of 25 billion euros (financed by EU, France and Italy), the tunnel construction has big environmental and economical objectives. The tunnel project management organization Tunnel Euralpin Lyon Turin (TELT) estimates the new faster rail connection can remove loads of up to 1 million heavy vehicles like trucks from roads. At the moment, 90% of freight between Italy and France is transported on roads.

An accidental traveler may ask why build a new tunnel next to an existing one that is known as the Frejus Tunnel? The old 13.7 km long tunnel that connects the towns of Modane and Bardonecchia was ready for traffic in 1871. To cross the Frejus Tunnel trains have to be able to ascent to 1388 meters and negotiate tight turns. The new tunnel is built at maximum altitude of 580 meters with low gradients and wide curves. It means that heavy freight trains are able to travel through the new tunnel.

Another longest in the world tunnel project is underway in northern Europe: an underwater tunnel that connects Germany and Denmark. The Fehmarnbelt will be the longest underwater tunnel (18 km) in the world built both for train and road traffic.