Switzerland unlocks the Basel bottleneck

The Federal Office of Transport (BAV) granted the planning approval for the main works to adjust the profile on the section between Basel St. Johann and Basel SBB in mid-December. This will create the structural conditions on the Swiss side to enable freight trains with 4-meter high semi-trailers to operate regularly over the left bank route to France and further to the NEAT base tunnels at Gotthard and Lötschberg. The main works are set to begin in 2026 and are expected to be completed by the end of 2029.

Freight Transport through the Metropolis

The aim of the project is to make rail freight transport more competitive and to shift additional alpine-crossing transports from road to rail. Four-meter high semi-trailers are increasingly establishing themselves in European freight transport, as they offer shippers and transport companies clear logistical and economic advantages. However, to transport these units by rail, a larger clearance profile is required, which many existing routes do not meet.

The core of the measures in Basel includes lowering tracks in the Kannenfeld and Schützenmatt tunnels as well as under the road overpasses Allschwilerstrasse and Oberwilerstrasse. In both tunnels, the tracks will be lowered by about half a meter, and the overhead lines will be adjusted. Additionally, a widening of the tunnel arch on the Rhine side is planned for the Kannenfeld tunnel to create an escape route. Under other overpasses, such as at Wanderstrasse and Marschalkenstrasse, adjustments to the overhead lines will suffice. The lowering will begin on open track, allowing the tracks to be ramped into the structures. At the same time, numerous utility and stream crossings under the railway line will need to be adjusted.

In parallel with the profile adjustment, SBB will utilize the project perimeter for extensive maintenance measures. Between the Kannenfeld tunnel and the Birsig bridges, the superstructure of both tracks will be completely renewed. Additionally, the two single-track Birsig bridges will be refurbished. Planned works include the renewal of corrosion protection, a new sealing of the bridge slabs, as well as the replacement and reinforcement of the bridge bearings. The goal is to ensure that the structures remain safe and reliable for at least another 50 years.

Works During Ongoing Operations

To minimize the impact on passenger and freight traffic, construction will take place while operations are ongoing. Instead of a multi-year total closure, only one of the two tracks will be closed for extended periods. Additionally, SBB will establish temporary track changes to halve the length of single-track sections and limit capacity losses. Nevertheless, restrictions in rail traffic and individual total closures on weekends are planned during the construction period.

The costs for the profile adjustment and track renewal amount to approximately 114 million CHF and will be financed through the federal commitment credit for the 4-meter corridor projects. An additional 7 million CHF is allocated for the refurbishment of the Birsig bridges, which will be covered by the performance agreement between the federal government and SBB.

To enable 4-meter freight transport to operate regularly via France, complementary profile adjustments on the French side are necessary. A corresponding letter of intent was signed by Federal Councillor Albert Rösti and the French Minister of Transport in February 2025. The goal of both countries is to create an additional, efficient left bank access route to the NEAT axes, thereby sustainably increasing the robustness of European rail freight transport.