The operation marked the 900-day countdown to the completion of the project, which is scheduled for December 2016.
All installations over the whole length of the twin-bore tunnel, including track, catenary, power supplies, signalling and telecommunications systems are due to be completed in October 2014 and the first test runs through the entire tunnel will be made in 2015.
The tunnel’s inauguration will take place in the first week of June 2016. Leuthard said: "On the weekend of 4 June 2016, there will be a big celebration for the public. People of all ages will be able to participate in the project’s completion and experience the tunnel. One or two days beforehand, the official opening with national and international guests will take place. Preparations for the opening ceremony will begin soon."