TerzoValico Genoa RailInfrastructure UndergroundConstruction

Polcevera ventilation tunnel completed for Italy’s Terzo Valico project

*Excavation works inside the 2 km Polcevera ventilation tunnel, part of Italy’s Terzo Valico dei Giovi and Genoa Junction project. Source: Tunneling Online (image by RFI)*

Excavation has been completed on the 2 km Polcevera ventilation tunnel, a key underground element of Italy’s Terzo Valico dei Giovi and Genoa Junction railway project. The tunnel forms part of a wider infrastructure programme designed to improve rail connectivity between Genoa, northern Italy and the European Rhine-Alpine Corridor.

The works were carried out for Rete Ferroviaria Italiana, part of the FS Italiane Group, with construction led by the Webuild group through COSSI Costruzioni. The tunnel was excavated using traditional excavation methods and required careful planning because of its urban and railway interface constraints.

The Terzo Valico dei Giovi and Genoa Junction project is one of Italy’s most important rail upgrades. It will strengthen connections between the Ligurian ports, northern Italy’s industrial regions and the wider European rail network. Once complete, the new railway infrastructure is expected to reduce journey times between Genoa and Milan to about 50 minutes while increasing capacity and reliability for both passenger and freight services.

The tunnel was excavated using multiple fronts to optimise programme delivery while managing complex underground conditions. Source: Ground Engineering

The Polcevera ventilation tunnel presented significant technical and logistical challenges. One of the most critical sections passed beneath the active Genoa to Milan railway line, with excavation taking place only about 18 m below the tracks. Rail services remained operational during the works, making settlement control, monitoring and construction sequencing essential.

To accelerate progress, the contractor worked from four excavation fronts. The first front tackled the section below the railway. From February 2025, two additional fronts were opened and advanced in opposite directions along the tunnel alignment. A fourth front focused on enlarging the tunnel profile and creating underground chambers for future ventilation equipment.

This multi-front strategy helped optimise the programme while maintaining operational and safety standards. It also reduced the dependency on a single excavation direction, which is especially useful in complex underground works where geology, access and logistics can influence progress.

Although ventilation tunnels may receive less public attention than main rail tunnels, they are vital for safe and reliable railway operation. They support air movement, smoke control, maintenance access and emergency management within underground railway systems.

The underground chambers created along the Polcevera tunnel will house equipment for the future ventilation system. This infrastructure will become part of the wider operational safety framework for the Genoa Junction and Terzo Valico corridor.

The project demonstrates the importance of secondary underground works in major transport schemes. Main tunnels, junctions and viaducts cannot function effectively without supporting systems such as ventilation, access, drainage, power, signalling and emergency infrastructure.

The completion of the Polcevera ventilation tunnel is therefore more than a local tunnelling milestone. It marks progress on a strategic European rail corridor that will improve freight movement, reduce pressure on existing lines and support better integration between ports, cities and industrial regions.

Sources: tunnellingjournal.com, geplus.co.uk, tunnelingonline.com