Project Profile: Gotthard Base Tunnel (GBT), Switzerland

The Gotthard Base Tunnel (GBT) is a 57.1km twin-bore railway tunnel through the Swiss Alps, representing a pinnacle of modern civil engineering. As the world’s longest and deepest railway tunnel, it forms the centrepiece of the New Rail Link through the Alps (NRLA) project, engineered to revolutionise European freight and passenger transport on the vital Rotterdam-Genoa corridor.

Technical Specifications

Tunneling and Route Design: The GBT consists of two single-track tubes, connected by cross-passages every 325 metres for emergency access. Its defining feature is a near-level, low-gradient profile, which minimizes the energy required for traction and allows for heavier and faster train services compared to the old mountain route. Construction was a monumental undertaking, divided into five sections and executed simultaneously using four massive Herrenknecht Tunnel Boring Machines (TBMs) for main excavation and traditional drill-and-blast methods in challenging geological zones. With up to 2,300 metres of rock overburden, managing high temperatures and rock pressure was a primary engineering challenge.

Signalling and Safety Systems: The tunnel’s operations are governed by the European Train Control System (ETCS) Level 2, supplied by Thales. This technology eliminates the need for conventional lineside signals, transmitting movement authority directly to the train’s cab and enabling continuous speed monitoring. This enhances safety and allows for a higher density of traffic. The safety infrastructure is extensive, featuring powerful ventilation systems from ABB to control air quality and manage smoke in an emergency, comprehensive fire detection systems by Siemens, and two multifunction stations at Sedrun and Faido that serve as emergency stops and access points for rescue services.

Key Takeaways

• Revolutionised Trans-Alpine Freight: The GBT’s flat trajectory allows freight trains up to 4,000 tonnes to traverse the Alps, significantly increasing capacity and enabling a modal shift from road to rail on the vital Rotterdam-Genoa corridor.
• Benchmark for Mega-Project Engineering: The project set global standards in deep tunnelling, managing complex geological conditions, and implementing large-scale logistical operations, providing a blueprint for future infrastructure projects.
• Enhanced European Passenger Connectivity: By slashing journey times between Zurich and Milan by approximately one hour, the tunnel has strengthened north-south European high-speed rail integration, boosting economic and social connectivity.

Frequently Asked Questions (FAQ)

How long is the Gotthard Base Tunnel?
The Gotthard Base Tunnel is 57.1 kilometres (35.5 miles) long, making it the longest railway tunnel in the world. Its route runs deep beneath the Swiss Alps between the towns of Erstfeld in the north and Bodio in the south.

What technology makes the Gotthard Base Tunnel safe?
The Gotthard Base Tunnel’s safety is ensured by a multi-layered system, centrally managed by the European Train Control System (ETCS) Level 2. This advanced signalling provides continuous in-cab monitoring and train control, backed by a sophisticated ventilation system, fire detection sensors, and two emergency stop stations with dedicated escape routes.