Schwarzwald, which is the highest non-alpine mountain in Germany, is located in the south-west of the country. One of important regional railway line section there had to be renovated, to meet the modern requirements on effectivity and efficiency. The task for Euro Alliance Tunnels was renovation of five single railway tunnels on this section.

The tunnels with total length of 1.236 m - Dögginger (535 m), Kapf (203 m), Setze (104 m), Hörnle (228 m) and Finsterbühl (166 m) had to be lowered in the bottom to create space for electrification in the upper section of the tubes. Additionally to these excavation works the old lining and dewatering system in all tubes were renewed. Those works contained injections, spraying concrete works, installation of micro piles, assembling of special bars in the bottom areas, concrete aprons and new drainages for the total length of the tubes.   

We have excavated appx. 7.700 m3 rock. For reinforcement we have used appx. 206 t steel, 1.000 m3 spraying concrete and in total 11.000 m micro piles.

We had to cope with narrow conditions in the tubes - with the use of special machinery. But this was not the only challenge. The logistics, difficult conditions for materials´ transports and also the mountain weather conditions made this project very special.