High temperatures are causing significant rail disruptions across the Bernese network, with heat-induced track deformations forcing speed restrictions and line closures. According to reports from the Jungfraubahnen, BLS, and SBB, the ongoing heatwave has impacted multiple transit routes, leading to delays and the implementation of replacement bus services.
Impact on Regional Rail Services
The Jungfraubahnen confirmed that tracks have deformed in six locations between Zweilütschinen and Grindelwald, as well as between Zweilütschinen and Lauterbrunnen. These defects on lines R61 and R62 mandate slower train speeds, which will result in ongoing delays. The operator expects these restrictions to remain in place until at least the end of the daily operating schedule and warns that similar heat-related issues may recur during upcoming high-temperature days.
Further disruption is affecting the Biel-Sonceboz-Sombeval route between Biel and Reuchenette-Péry. Due to track damage, lines RE4 and R41 are currently suspended, with replacement bus services currently in operation.
The track between Solothurn and Moutier, which experienced heat-related deformations on Tuesday, was only returned to service in early June following a two-year renovation project that included repairs to the Weissenstein tunnel.
Engineering Challenges and Maintenance
The BLS addressed the track failures on the Solothurn-Moutier line, which was closed from Tuesday at 2 p.m. until Wednesday at 6 a.m. A BLS spokesperson stated that the tracks were manually straightened and tamped, with the gravel ballast requiring further compaction. The company noted that while the newly installed steel sleepers are designed for longevity, they require an “in-driving” period during which the track bed settles, leaving the infrastructure temporarily more susceptible to thermal stress.
The incidents highlight the delicate balance between modern infrastructure upgrades and environmental extremes. While track hardening—such as the installation of durable steel sleepers—is intended to stabilize long-term operations, these transitions reveal a “settling” vulnerability. During heatwaves, this means even recently renovated sections may require intensive, manual maintenance to prevent service failures until the ballast has fully compacted.
Resolution of Additional Network Disruptions
Beyond heat-related damage, the SBB reported two other service interruptions in the Bern area on Wednesday. The line between Bern and Freiburg faced delays due to a passenger accident, while the route between Bern and Kerzers was restricted following cable damage during construction work. Both issues were resolved by late Wednesday afternoon, according to SBB statements.
Frequently Asked Questions
Why are the tracks deforming?
The deformations are a direct result of the current heatwave, which causes the metal rails to expand. In some cases, such as on the newly renovated Solothurn-Moutier line, the ballast and sleepers have not yet fully settled, increasing the risk of movement.
Which lines are currently affected by heat-related damage?
The lines R61 and R62 in the Bernese Oberland are operating with speed restrictions. Additionally, the route between Biel and Reuchenette-Péry is currently closed, with replacement buses serving the RE4 and R41 lines.
Are these disruptions permanent?
No, the operators are actively managing the damage. The BLS reported that the Solothurn-Moutier line was repaired and reopened within 16 hours. However, operators indicate that further heat-related restrictions could occur as long as high temperatures persist.
How have these recent rail disruptions impacted your travel plans in the Bern region this week?
