Project Profile: Ceneri Base Tunnel (CBT)

The Ceneri Base Tunnel (CBT) is a pivotal component of Switzerland’s New Rail Link through the Alps (NRLA), creating a continuous flat railway route from the North Sea to the Mediterranean. As a twin-tube railway base tunnel, it provides a high-capacity, high-speed corridor that dramatically enhances freight logistics and passenger travel between Northern and Southern Europe. This profile details the technical specifications and strategic impact of this critical infrastructure asset.

Technical Specifications

The Ceneri Base Tunnel consists of two 15.4 km single-track tubes, spaced approximately 40 meters apart and interconnected by 48 cross-passages for safety and maintenance. The project’s geology necessitated a hybrid excavation approach. Approximately 80% of the tunnel was excavated using Tunnel Boring Machines (TBMs), specifically two 9.7m diameter Main Beam TBMs supplied by The Robbins Company. The remaining sections were constructed using conventional drill-and-blast methods, particularly in more complex geological zones near the portals. The tunnel’s flat trajectory, with a maximum gradient of just 0.8%, is engineered to allow heavy freight trains to traverse the Alps with minimal traction power, significantly increasing efficiency. The infrastructure within the tunnel features a slab track system for high-speed stability and is equipped with ETCS Level 2 signalling, enabling high-density traffic flow under centralized control from the Pollegio Operations Center.

Key Takeaways

• Completion of the NRLA Flat Route: The CBT is the final major component of the New Rail Link through the Alps, creating a continuous low-gradient rail corridor through the Swiss Alps when combined with the Gotthard and Lötschberg Base Tunnels.
• Boost to European Freight Corridor: The tunnel removes a significant bottleneck on the Rotterdam-Genoa freight axis, allowing for longer, heavier, and more numerous freight trains, thereby shifting significant cargo volume from road to rail.
• Reduced Passenger Travel Times: The project has drastically cut journey times within the Canton of Ticino and on the international Zurich-Milan route, reducing the travel time between the two cities to under three hours.

Frequently Asked Questions (FAQ)

What is the main purpose of the Ceneri Base Tunnel?
The main purpose of the Ceneri Base Tunnel is to create a flat, high-speed rail link through the Alps. For freight, this allows longer and heavier trains to pass with greater efficiency, shifting cargo from road to rail. For passengers, it significantly reduces travel times, particularly between the key economic centers of Zurich and Milan.

How was the Ceneri Base Tunnel constructed?
The Ceneri Base Tunnel was constructed using a combination of methods. The majority of its 15.4 km length was excavated by two large Tunnel Boring Machines (TBMs), which are ideal for consistent rock conditions. The remaining portions were built using the conventional drill-and-blast technique, which provides more flexibility in variable or challenging geological formations.