Quadrupling of the urban railway link in the Porta Susa-Stura section on the Turin-Milan railway line.
The intervention involves an urban section of about 4.5 Km and includes the undergrounding of the existing railway line (Turin-Milan), and the doubling of the number of tracks bringing them from 2 to 4.
The construction works have been carried out without interrupting the existing railway service and have been managed in order to minimize the impact on traffic and on commercial activities. Detailed studies were carried out on: the construction works operative phases, the opening of the mobile worksites, the location and organisation of the fixed worksites, the provisional works, the temporary rail and road diversions, and to the identification of the most suitable construction technologies to satisfy the Client’s objectives in terms of time, costs, safety, and impact within the construction stage.
About technologies, a rotating hydro tunnel boring machines for the digging out of the bulkheads (about 320,000 m2) in the highly cement-bound soil below the city; the consolidation of the foundations of buildings within 5 m from the bulkheads, and special systems used to achieve the total waterproofing of the railway tunnel.

MAIN WORKS
• Two parallel tunnels, complete with rails, ventilation system, fire prevention and safety facilities;
• Two underground stations (Porta Susa and Rebaudengo), one building station (Dora), one open-air station (Stura);
• A two underground levels crossing infrastructure, between the two tunnels and the foreseen urban subway;
• A tree-line (per direction) city access avenue of 4.5 km, with an underground section of 0.6 km (Piazza Statuto), thus creating an underground structure on two levels: the deeper railway level, and a road tunnel immediately above;
• A two-level bridge (road and rail) across the River Dora Riparia, 42 m long, with 3 spans;
• A four-leaf clover junction between the Corso Grosseto crossroads and the Casselle airport motorway link.