ÅF connecting Switzerland

A 15.4 kilometre long tunnel under Monte Ceneri will nearly halve the travelling time between Locarno and Lugano. With this project ÅF contributes to a sustainable traffic development for the Ticino region.

The New Railway Link through the Alps, NRLA, will provide a faster north-south rail connection in Switzerland. On June 1, 2016 the Gotthard Base Tunnel was completed and full train service began on December 11, 2016. This project included a twin tube, single track railway tunnel, connecting Erstfeld with Bodio. The opening of the next phase, a critical 15.4 kilometer long rail link base tunnel under Monte Ceneri, is scheduled for 2020 and will complete the new level route from Erstfeld to Lugano.

Similar to the Gotthard Base Tunnel, the Ceneri Base Tunnel consists of two single-track tunnels, connecting the Piano di Magadino (near Bellinzona) with Lugano. The distance between the single tubes is about 40 meters. The longer Gotthard Tunnel includes cross passages linking the two tunnels every 325 meters and a connection on the north and south ends to the existing main train line system of the SBB (Swiss Federal Railways). This new link is being constructed at the request of the Canton of Ticino in order to meet its long-term regional traffic needs. The connection will reduce the journey time between Locarno and Lugano from today's 59 minutes to only 31 minutes enabling the entire region to become one greater metropolitan area.

Because the Ceneri Tunnel is shorter than the Gotthard Tunnel, track crossovers or multifunction stations are not required. A bifurcation structure, Sarè, will permit future additional traffic links from the NRLA axis to the south, without any interruption to rail traffic.

The Ceneri Base Tunnel includes:

• Twin tube single track railway tunnels, 15.4 km long
• Train speeds of up to 250 km/h
• Total length of underground link approx. 40 km
• Excavation area of one single tube between 48 and 87 m²
• Excavation volume approx. 3.5 million m³
• Capital improvement costs of approximately CHF 2'500 Mio.

The entire Ceneri Base Tunnel is located in the crystalline bedrock of the southern Alps. It passes through a complex and heterogeneous formation. The maximum rock overburden is up to 800 meters, the minimum only a few meters. Due to geological characteristics, the mountainous landscape, environmental and methodology factors a middle logistic heading was constructed to facilitate the main activities and logistics of the construction site.

This intermediate heading in Sigirino consists of comprehensive external logistics:

• Motorway junctions
• Village for miners, infopoint and offices
• Worksite areas used for construction equipment and materials
• Railway linking
• Concrete batch plant
• Wastewater treatment plant
• Disposal site for the excavated material

In Sigirino an underground cavern with a volume of about 130’000 m³

The Ceneri Base Tunnel was excavated entirely by drilling and blasting between 2007 and 2016. The bulk of the excavation was performed simultaneously from the middle at Sigirino in both directions outwards. The portals at Vigana and Vezia were completed via small inward facing connection stretches, minimizing time and costs. A double lining was installed along the entire length of the tunnel. The external ring provides temporary stability during construction, while the internal ring provides long-term stability for the entire life of the project. The internal ring was mainly built in unreinforced concrete. Umbrella seals and drainage lines were installed between the two rings for protection and drainage of groundwater.

ÅF was awarded and completed the public contract for the planning and construction management of the Ceneri Base Tunnel, including all project phases from predesign to construction and commissioning.