On Monday, January 19, the European Court of Auditors released the update of the EU transport megaprojects Report, published in 2020, which studied eight infrastructure projects under construction in thirteen European Union countries. These include the Lyon-Turin cross-border section, which is in an advanced state of construction between France and Italy, according to the final design approved in 2015, whose main work includes two parallel 57.5-km-long rail tunnels. Commissioning of the railway line is scheduled for the end of 2033 with a total investment of €11.1 billion.

The premise of the Court of Auditors

There is no doubt that complex works such as cross-border infrastructure face major technical, administrative and social challenges. As the Court recalls:

‘Since 2020, the EU has been significantly affected by the COVID-19 pandemic and Russia’s war of aggression against Ukraine. The eight TFIs faced the same challenges, as well as needing to adapt to an evolving regulatory framework. Furthermore, some of the TFIs were subject to unexpected technical challenges such as geological constraints in the excavation of tunnels, which contributed to additional costs and delays.’  

The Mont Cenis base tunnel, a complex project

The auditors recognize the Lyon-Turin railway line as one of the projects that can contribute to the European single market through a more interconnected and efficient network. Conceived within the framework of two States with different approaches and rules that required a great deal of harmonization work, the project is among the most complex in the world in the rail sector: a total of 164 km of tunnels through 15 geological areas under the Alps between France and Italy.
In this context, the study phase was very long: it started in the late 1990s with an initial design (which envisioned a single tunnel) that was later discarded for safety and capacity reasons. Then the project evolved into the one currently being implemented: a twin-tube tunnel, compliant with new European standards, for freight and passenger transport, designed on the basis of 113 km of exploratory works and finally approved by the 2015 international agreement.
Therefore, the Court’s comparison of time and costs in the 1990s with those of the project validated in 2015 does not reflect reality.

The evolution of the lifetime cost

The 2015 Lyon-Turin final project estimated a budget of € 8.6 billion (2012 value). In 2024, after the award of the contracts for all civil works and the end of the Covid contingency, TELT updated the lifetime cost to €11.1 billion (2012 value) with commissioning in 2033. 

This update, shared with the States and the EU, is based on three main, largely external factors that have had a structural impact on the progress of the construction sites. 

In addition, in 2025 Italy, France and the European Commission signed the implementation decision for the entire Lyon-Turin railway line (including the national sections), whereby they commit to complete the work program and achieve the common goals, regardless of how and when the individual entities finance the entire infrastructure.