Under an agreement signed by the Swiss and Italian governments in January, Switzerland will contribute €120m towards increasing the loading gauge on the route to accommodate lorry semitrailers with a corner height of 4m. The project is a key element of the Swiss Federal Council's plan to create a continuous 4m corridor from Basle to Northern Italy via the Gotthard Base Tunnel.

The specification agreed for the project encompasses 170 separate measures including adjustments to tunnel walls, platform canopies, overbridges, signalling, and catenary.

The Italian government will also fund €40m worth of enhancements on the Chiasso – Milan line as part of the project.

Under the terms of the agreement, the work on both lines should be finished by the end of 2020, following the completion of both the Gotthard base tunnel and the Ceneri tunnel. This will allow the carriage of 4m semitrailers on the entire route through Switzerland to Gallarate/Novara via Luino and Milan via Chiasso.

At present the only 4m rail corridor though Switzerland is the congested Lötschberg – Simplon route.