The Lyon-Turin high-speed rail project, a major cross-border infrastructure initiative connecting France and Italy, has faced significant cost increases over the years. Originally estimated at 36.3 billion euros, the project’s total cost has now risen to 66.5 billion euros, with the cross-border section alone seeing a 127% increase, from 5.2 billion euros in 2019 to 11.8 billion euros by November 2025. The project, which aims to connect Turin in Italy with Lyon in France, has also seen delays, with the completion date now projected for 2033—over 18 years after the original 2015 target. As of autumn 2025, only 19.2 kilometers of the 115 km main tunnel have been excavated, along with 26.1 km of auxiliary galleries. Work on the base tunnel under Mont-Cenis, a key section of the project, is less than one fifth complete, despite more than a decade of tunneling. Around 3,000 workers are working in rotating shifts, 24 hours a day, seven days a week, to remove 37 million tons of rock. Eighteen excavation fronts are currently active, with tunnel boring machines making slow progress through the mountainous terrain. Unfortunately, three workers have died in accidents on the site in the past two years. The delays and rising costs have sparked ongoing debates among local authorities, environmental groups, and transportation advocates. Some argue that the project is essential for shifting freight from roads to rail, reducing traffic and pollution in the Alps. Others question the project’s viability, especially with the French access routes not expected to be completed until 2045—over 20 years after the tunnel itself is projected to be finished. This raises a practical concern: what use will the tunnel be if the tracks leading to it are not ready for decades? The Lyon-Turin project is one of two major European transport projects contributing to significant cost overruns in the broader trans-European transport network. While the cross-border tunnel is progressing, albeit slowly, the French side of the infrastructure remains far behind. For now, trucks continue to cross the Alps by road, and the uncertainty surrounding the project’s future use remains a key issue for both travelers and taxpayers.