Brenner Base Tunnel: „Mountain Festival“ at the record tunnel construction project

After completion of the construction work, the Brenner Base Tunnel will be the world’s longest tunnel at 64 kilometers. After about 20 years of construction, it will connect Austria and Italy as a railway line. The 8.5-billion-euro project is expected to be completed in 2027. At the halfway point, it’s time for a closer look at the high-performance axle that will connect Austria and Italy.

What good is the Brenner Base Tunnel?

Brenner Basis Tunnel

The Brenner Base Tunnel is an important element of the Scandinavia-Medterranean TEN Corridor from Helsinki to La Valletta, Malta (pink). © BBT SE

Currently around 2.25 million trucks pass through the Brenner Pass every year. Looking at the total transit volume of the Central Alps, this accounts for 40 percent. For the nature at 1371 meters, this traffic volume is a major burden. The Brenner Base Tunnel is supposed to shift transport to the rail and, thus, contribute to relaxation. Therefore, especially the neighbors support the tunneling project.

In addition, the Brenner Base Tunnel will also make passenger transport by rail more attractive. Thus, travel time between Innsbruck and Franzensfeste in Italy will be reduced from 90 to 25 minutes. After the planned completion of the transport corridor through the central Alps, the passage from Munich to Verona will take only four hours instead of seven hours.

Facts and figures about the Brenner Base Tunnel

A total of 230 km of tunnels and galleries will pass through the mountains between Tulfes and Innsbruck in North Tyrol and Franzensfeste in South Tyrol after completion of the work. Because in addition to the two 55 km long main tunnel tubes with a diameter of 8.1 meters, which are each equipped with a track for passenger and freight trains, the tunnel builders cut supply and safety tunnels through the rock.

At a distance of 333 meters, the two track tubes are connected with a crosscut. This serves as an escape route. There are also four lateral access tunnels.

Even before the construction of the main tubes began, an additional, smaller exploratory tunnel was built. It was supposed to give information about the condition of the rock and, thus, a clue for the estimation of construction costs and time. Upon completion of the Brenner Base Tunnel, the exploration gallery will take on a crucial role in the drainage and maintenance of the tunnel system.

“#BrennerBaseTunnel: The world’s longest #Tunnel will relieve the #BrennerPass. Right now it is halftime for the #infrastructure project of superlatives.“

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Status quo: Halftime for the Brenner Base Tunnel

Workers while preparing explosives for the Drill-and-blast excavation. © BBT SE

Halfway through the project, a positive conclusion can be drawn: More than 70 kilometers of tunnel have already been cleared from the mountain. Further meters are cut by a tunnel boring machine. The 200-meter-long system uses 1,600 tons of pressure. From 2019, six of the monsters will be in operation.

In addition to drilling, the tunnels are blown into the rock with the help of blasting. This is done according to the so-called New Austrian Tunneling Method (NÖT). After each explosion, the created spaces are secured with shotcrete.

Whether the tight schedule can be met is, however, unclear. Although the experience has been positive so far, there are factors that could still hamper progress. Poor rock, for instance, presents tunnel builders with new challenges every day. Plus, anyone who has ever been involved in such a mega-project knows that delays are the rule rather than the exception.