Three professions, one shared commitment

While Romain coordinates time and resources, surveyors ensure that every metre excavated is exactly where it should be. 

Stéphane Vial, Head of the Surveying Team on the construction site, brings together more than 32 years of experience in tunnelling projects from the Lyon metro to CERN, and now the Lyon–Turin project. Trained as a surveying technician, he acquired much of his expertise directly in the field. Since 2018, he has been with Implenia as Lead Surveyor, first at CERN and then on the CO08 site.  

“On a tunnel construction site, you often start with an empty area, and by the end you see an enormous transformation. It’s fascinating,” says Stéphane. 

He supervises a team of three people with different work arrangements: some operate on a rotating shift system, including night on-call duties, while others work weekdays from Monday to Friday. For him, the world of tunnelling is also a place of encounters, as all trades eventually cross paths even when they belong to different companies. 

José Pereira Torres, who has been working in the tunnelling sector since 2016, began his career as an assistant surveyor in earthworks in Portugal before continuing in France. He took part in landmark projects such as the Grand Paris Express, on line 15 and line 11, before joining the Lyon–Turin project. 

“Precision is essential. An error of just a few centimeters in a tunnel can have consequences for the entire project,” José points out. 

Using their instruments – total stations, theodolites, 3D scanners, gyroscopes and lasers along with software such as Amberg Tunnel and AutoCAD – they ensure the precise setting-out of the vault, monitor convergence, and carry out structural checks. They work closely with excavation teams, geologists and QSE managers to guarantee safety and compliance. 

“The world of tunnelling is intense. It requires rigour, insight and a great deal of adaptability,” Stéphane concludes. 

Although their roles differ, Romain, Stéphane and José share a common objective: to advance the tunnel with precision and efficiency. One anticipates and coordinates, the other measures and monitors. Together, they illustrate the complexity and richness of underground work, where every decision and every measurement matters. 

Their commitment not only ensures compliance with deadlines and standards, but also guarantees that, in a few years’ time, trains will pass through this tunnel safely. A collective achievement, orchestrated with care and passion.