Tunnels and Underpasses

Tunnel construction requires a combination of civil engineering, advanced technical installations, and specialised project management. Modern tunnel projects integrate structural works with safety systems, ventilation, lighting, drainage, and control technology to ensure long‑term reliability. Contractors with rail and civil expertise deliver both road tunnels and rail tunnels, merging construction with lifecycle‑oriented asset management.

Tunnel and underpass construction brings together many disciplines: structural engineering, geotechnics, MEP systems, safety installations, rail systems, cabling, telecom, power supply and monitoring. Successful delivery requires end‑to‑end coordination, often managed by organisations that combine in‑house specialists with trusted long‑term partners across the value chain. This integrated approach ensures seamless execution in complex environments and supports long‑term operability.

Tunnels depend on a broad suite of tunnel technical installations, including fire‑safety systems, ventilation, lighting, signalling, traffic control, emergency communications and structural monitoring. These systems must be designed, installed and maintained according to strict safety and performance standards. Regular inspections and data‑driven maintenance are essential for keeping these installations reliable throughout the tunnel’s lifecycle.

Tunnel maintenance includes routine inspections, cleaning, functional checks of technical systems, and structural assessments. Rail‑sector standards classify tunnels by geometry, lining material and condition, and require periodic and extraordinary inspections to assess structural integrity and safety risks. Asset‑management‑driven maintenance ensures tunnels remain safe, available and fit for increasing traffic volumes over decades.

Railway tunnels must meet additional requirements such as accommodating overhead lines, track systems, power supply, signalling, emergency walkways, drainage and smoke‑control measures. They also require precise track geometry and maintenance methods suited for high‑speed or heavy‑rail operation. Leading European firms specialise in design, construction and renewal of railway tunnels, ensuring safe integration with the broader rail network.

In both rail and road environments, work often takes place under live conditions. This requires detailed staging, temporary diversions, night or weekend possessions, and precise coordination of civil works, MEP systems and tunnel‑technical installations. Rail organisations in the Netherlands, Scandinavia and Italy routinely work in active networks, applying strict safety regimes and disciplined planning to minimise disruption.

Underpasses require robust structural design to manage soil loads, groundwater pressure and proximity to rail or road traffic. Typical works include cut‑and‑cover construction, pre‑fabricated elements, foundation works, waterproofing, drainage and integration with surface infrastructure. Engineering teams also coordinate utilities, telecoms and mobility interfaces to ensure safe and efficient movement above and below ground.

Innovation comes from combining specialised tunnel engineering, advanced excavation methods, digital design tools, smart asset‑management systems and international knowledge exchange. For example, Italian expertise within the Strukton group includes high‑precision construction and renewal of rail tunnels and underground metro lines, contributing decades of experience and advanced methods to tunnel projects across Europe.