The year 2026 is also shaping up to be challenging for rail links crossing Switzerland from north to south, due to extensive construction sites affecting the main transalpine corridors. Even more discouraging is the forecast that normal operations will only resume in 2029. This is the outlook outlined by Datec, the Swiss Federal Department of Transport. The expansion and modernisation of the access routes to the Alpine transversals require major works with significant repercussions for freight services.
The most difficult situation is expected on the northern routes, particularly those connected to the German rail network. North of the Alps, the most important access point is Germany’s Rhine Valley Railway, used by more than one hundred trains a day. Capacity on this corridor is now at its limits, and although quadrupling works are underway between Karlsruhe and Basel, they are not expected to be completed before 2040.
South of Switzerland, towards Italy, the situation appears less critical, though far from ideal, as traffic is distributed across the Chiasso, Luino and Domodossola axes. Construction works mainly affect the Simplon line, which still needs to be upgraded to accommodate all intermodal trains without gauge restrictions. The longstanding bottleneck of the Varzo spiral tunnel also remains unresolved and would require extensive reconstruction.
Datec outlines several restrictions for freight traffic caused by modernisation and upgrade projects scheduled for 2026. During the summer, the Rhine Valley Railway between Karlsruhe and Basel will undergo a full closure—first for one week and later for three weeks—forcing trains onto alternative routes. In the same period, a two-month closure is planned on the Simplon line between Iselle and Domodossola. Further hourly or partial restrictions are also expected on this corridor.
In the second half of 2026, major disruptions will shift to Germany on the right bank of the Rhine between Cologne and Wiesbaden, where a five-month full closure is scheduled. During this period, all rail traffic will be diverted to the left bank, placing heavy strain on already limited capacity as freight will have to coexist with passenger services. The restrictions will not end in 2026, as further disruptions are already scheduled for the following two years.
In June 2027 the section between Offenburg and Leutersberg, on the Karlsruhe–Basel corridor, will operate on a single track. The situation will deteriorate further in 2028 when the same section will be fully closed from mid-August to mid-September. Also in 2028, a likely six-month closure is expected north of Domodossola to allow the refurbishment and reconstruction of a railway bridge. These are only the main works; traffic will in fact face numerous sites across the entire network.
According to Datec, normality is expected to return only in 2029, as German infrastructure manager DB InfraGo plans to complete the first phase of works that will allow more train movements on the Rhine Valley Railway, making the line less vulnerable to disruption. The upgrade works on the Simplon line are also set for completion by 2029.
Piermario Curti Sacchi
