Why Switzerland is Building a Second Gotthard Road Tunnel to Secure Europe’s Alpine Corridor

Overview

The B1M explains why Switzerland is building a second Gotthard Road Tunnel to secure Europe’s Alpine corridor. The aging Gotthard Road Tunnel will be upgraded while traffic continues, using parallel TBMs and a safety gallery to avoid long closures. The project faces a major ground problem Goosebis shear zone, causing a temporary TBM stoppage and a multi million CHF setback. It aims for a 2030 completion, with traffic distributed in two tubes and one emergency lane, while a portion of excavated material is reused for concrete, road surfaces, and new habitats. The video also places the effort in a broader context of Europe’s rail and road networks through the Alps and policy constraints on capacity growth.

Overview

The video from The B1M presents the Gotthard corridor as a critical Alpine route for continental Europe, linking the German and Italian borders via the A2 and the Gotthard base tunnel network. It explains why the Swiss government decided to construct a second Gotthard Road Tunnel not to add capacity in the sense of doubling traffic, but to allow the existing tunnel to be upgraded without interrupting flow. When the old single-tube tunnel operates in parallel with a new tube, traffic will run in single-file lanes with a hard shoulder in the other direction and improved safety features. This undertaking reflects Switzerland’s constitutional restriction on increasing Alpine transport capacity; the aim is reliability and resilience rather than merely moving more vehicles. The project timeline targets completion in 2030, with a substantial budget and a focus on safety and continuity of service during upgrades.

Background: The Alpine Corridor and the Gotthard Network

The A2 highway through the Swiss Alps is one of Europe’s most important transport arteries, and the Gotthard route has evolved from a historic pass in the 1400s to a modern multi-tube system. The Gotthard Road Tunnel, opened in 1980 after seven years of traditional drill-and-blast excavation, was once the world’s longest road tunnel and remains a vital route that must be maintained. The video emphasizes that the new tunnel will run in parallel with the old service tunnel or safety gallery, allowing upgrades to the aging tunnel without a lengthy shutdown. A parallel road-based solution helps preserve traffic flow while works progress, illustrating how modernization can be achieved without interrupting regional and continental mobility.

Construction Approach: TBMs, Parallel Tubes, and Safety Galleries

Construction uses tunnel boring machines (TBMs) Alessandra and Paulina, each more than 12 meters in diameter, excavating from opposite ends toward a meeting point near the tunnel’s middle. The TBMs work through diverse ground conditions while a safety gallery and precast lining segments provide permanent support. In contrast to the original Gotthard tunnel, which used drill and blast in many sections, TBMs offer faster progress and a more controlled excavation, especially through complex geology. The two tubes will be excavated in parallel, separated by a safety gallery that will eventually house ventilation, electrical service ducts, and other infrastructure to maintain tunnel safety and operations. Some sections will temporarily revert to conventional drill-and-blast methods where squeezing ground or fault zones complicate TBM progress. A major preparation phase included excavating portaling caverns and underground concrete production facilities to minimize surface footprint and to shield operations from avalanche-prone terrain.

Ground Conditions: Goosebis Shear Zone and Project Risk

A central technical challenge has been Goosebis shear zone, a large, highly faulted block of rock that created squeezing ground conditions. The project team predicted some complexity but encountered a zone where the TBM face could collapse if not properly managed. To manage this, portions of the tunnel will be excavated using conventional drill and blast as a safer method in high-pressure zones, providing immediate rock stabilization with anchors and shotcrete. The plan also includes an additional access tunnel that will allow crews to reach in front of the TBM and drill back toward it to free the cutter head if the machine becomes jammed. This setback has substantial cost implications, with an estimated 20 million Swiss francs added to the project, bringing total costs to around 2.0 billion Swiss francs or more, equivalent to roughly US$2.7 billion. Despite the setback, the project schedule remains anchored to a 2027 rendezvous and a 2030 completion, with a multi-shift, seven-day-per-week operation to accelerate recovery if further issues arise.

Materials and Environment: Excavated Rock, Lining, and Habitats

The two TBMs will excavate roughly 7.5 million tonnes of rock, with a portion reused in concrete and road surfaces and another portion redirected to Lake Lucerne for habitat restoration. The tunnel lining will consist of precast segments, installed by the TBMs, while service ducts carry utilities and high voltage cables. The project places a strong emphasis on safety, long-term reliability, and environmental considerations, including the reuse of excavated material to minimize waste and the creation of new aquatic habitats as part of the regional environmental program. The TBMs’ progress through different rock types and fault zones underscores the evolution of tunneling practice from traditional drill-and-blast to modern TBM-driven methods with strategic contingencies for hazardous ground.

Traffic, Policy, and Economic Context

The Swiss constitution restricts the capacity of Alpine transport routes, meaning the new tunnel will not automatically double traffic through the Alps. Instead, the project aims to improve reliability and reduce disruption by distributing traffic across two tubes with dedicated lanes and improved safety features. For historical context, queues in the single-tube Gotthard tunnel were a recurring problem, and the new tunnel is framed as a resilience measure to prevent a complete standstill if a major maintenance event or an unexpected ground issue occurs. The Swiss population approved the plan in a referendum, highlighting the public support for safeguarding an essential European corridor even when it does not necessarily increase capacity. The project also reflects the broader European need to maintain robust cross-border infrastructure to support rail and road traffic through the Alps and the ambitious but constrained approach to modernization.

Conclusion

Overall, the Gotthard replacement tunnel project represents a landmark in civil engineering that blends traditional preparation with modern TBM-driven construction, while addressing complex geology and a policy framework that prioritizes safety and reliability over simple capacity expansion. The new tunnel will enable upgrades to the old tube, safer and more reliable traffic management, and an improved cross-Alpine corridor for Europe. The B1M invites viewers to follow the project as it develops toward its 2030 completion date, and to consider how large-scale infrastructure projects balance engineering innovation, environmental stewardship, and public policy.