Final breakthrough of the east tube is due to take place next week. The entire tunnel has been excavated using conventional drill-and-blast techniques due to the region's complex geology, which ruled out the use of TBMs. The work is being carried out by the Condotte Cossi Consortium under a contract worth just under SFr 1bn ($US 990m).

Tunnel lining and concreting work and the installation of ventilation, drainage and power systems will continue for the rest of this year. Work on installing railway infrastructure is due to start in the middle of next year.

The twin-bore tunnel is due to open to commercial traffic in December 2020 as part of the New Railway Link through the Alps (NRLA), which also includes the Gotthard Base Tunnel. Like the Gotthard tunnel, Ceneri's running tunnels are are linked by cross-passages located at 325m-intervals.

The opening of the tunnel will reduce the journey time between Locarno and Lugano from 50 minutes to 22 minutes. However, as Mr Peter Füglistaler, director of the Swiss Federal Office of Transport (BAV), pointed out to about 1000 guests at the breakthrough, the importance of the tunnel extends far beyond the canton of Ticino and Switzerland: "With its policy of consistently transferring transalpine freight traffic from road to rail, Switzerland is exemplary in Europe," he said.