26.05.2020

Premiere for LVT HS (High Shoulders) in the new Bözberg tunnel

For several years, SBB has been implementing a 4-meter corridor on the Gotthard route. This means that also four-meter-high semi-trailers can be transported by rail, thus enabling the full potential of the New Rail Link through the Alps (NRLA). The new construction of the Bözberg tunnel in the canton of Aargau between Basel and Zurich is one of the largest individual projects of this expansion. The existing tunnel, dating from 1875, is not suitable for the transport of these trailers. It is now being replaced by a parallel, 2.7-kilometer long, new double-track tube and will be used as a service and rescue tunnel in the future. Work on the new Bözberg tunnel has been underway since autumn 2015 and regular operation will start as planned at the timetable change in December 2020.

Due to the geological conditions in the mountain, in some areas heaving of up to 26 mm is expected during the entire lifetime of the tunnel. In such incidents the originally planned ballasted track could have been adapted to the new situation by tamping. However, SBB prefers a slab track in long tunnels. SBB and Vigier Rail have therefore jointly developed the new LVT HS support that is perfectly suited to the exceptional requirements of the project. Maximum flexibility is one of the many advantages of the LVT system, allowing tailor-made solutions for every need.

LVT HS can compensate for heaving and at the same time for possible settlements in other areas. The new support has raised concrete shoulders, so that the compensating plates, so-called APW, which are already pre-assembled in the rail fastening system ex works, can safely transfer the forces arising from train passing into the concrete block. In order to bring the track back into the correct position, the APWs can be removed step by step in the event of a heaving of the tunnel invert, and in the event of a settlement of the tunnel invert of up to 25 mm HDPE plates can be inserted into the rubber boot of the LVT support. In both cases, the adjustment on the track can be carried out in short night-time closures without the use of large machines and without work on the track concrete.

Installation of the ballasted access line and the ballastless LVT track began in September 2019. Vigier Rail supplied B91 mainline sleepers and more than 13,000 LVT supports. In addition to the special LVT HS version, other versions of the LVT system are also installed, such as LVT Standard and – in the area of the level crossings at the five emergency exits – LVT Traffic.