The Bern region is an important hub in Switzerland's rail network. Due to various construction projects, the number of stabling areas for trains has been greatly reduced in recent years. The current "AS25, Bern West performance enhancement" project will also result in the loss of further stabling tracks. To compensate for this, SBB has now built a new stabling facility for long-distance and regional trains at Bern Bümpliz South station. At the same time, the two tracks were renewed over a length of around one kilometer.
Things got underway in January 2021: Our team from the track construction and civil engineering divisions began setting up the two installation sites and working on the track crossings for the new SBB cable system. In-situ concrete elements were prefabricated in advance for the cable shafts, which were up to three meters deep, and then gradually installed during the course of the construction work.
As the construction site is located on the Bern-Fribourg main line, it was necessary to ensure that trains could run on at least one of the tracks without being affected by the construction work. To this end, at the end of January we rammed a ballast support into the ground between tracks 1 and 2, consisting of four-meter-high steel girders and steel plates. This support enabled us to dismantle and renew Track 1 and the entire substructure of Line 1 in the first stage within five weeks. In the process, it turned out that the subsoil was worse than previously assumed. As a result, the material had to be replaced at a depth of around 30 centimeters over the entire route length of approx. one kilometer.
Similarly, in the second step, track 2 was rebuilt and reconstructed. After a further five weeks of single-track operation of rail traffic, we were able to complete track 2 over a length of approx. 1130 meters.
One switch each had to be replaced in both track 1 and track 2, and around 2000 cubic meters of material were excavated. In addition, our team installed a construction switch between tracks 1 and 2 in order to be able to divert train traffic from both directions onto one track during the track work. This work could only be carried out over the weekend, as the entire rail line had to be closed for this purpose. After the two tracks were completed, another total closure of the line took place: On this weekend, we not only removed the construction switch again, but also laid the new switches to the sidings.
The new sidings are divided into the north and south sidings. In the north, the facility now comprises three sidings for regional trains, each 200 meters long, and one siding with a length of around 450 meters. The south stabling facility already consisted of an old track, which we demolished and replaced with a track around 740 meters long.
To ensure that the trains that will be parked on the tracks in the future can be cleaned quickly and made ready for their next use, we installed new water taps on both sidings and laid seepage pipes to drain the areas. Each of the latter drains into one of the four newly installed underground seepage systems. We also laid about three kilometers of cable ducts for the new SBB cable system.
The sidings are located in a built-up area, which is why our contract also included the erection of noise barriers. After the necessary drilling for the micropiles, two new noise barriers with a length of 175 and 75 meters respectively could be installed from completely prefabricated elements.
The milestones set by the client were always met during the entire construction period - this was not a matter of course due to the pandemic and the additional work within the required construction time. Many thanks to the entire WALO construction site team for the super performance and the very good cooperation.
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