To create a barrier free station and add two elevators to the train station in Lauffen am Neckar the construction contractor Geo-Bohrtechnik had to face substantial challenges, these include restricted space, overnight working and trains continuing to operate. The aim of the work was to build small excavation pits on the platforms in order to be able to build shafts for the new elevators.
On the main and central platform, tangential pile walls DN 420mm with steel reinforcements were planned. The 70 boreholes with depths of up to 10m had to be carried out during ongoing railway operations at night and at a restricted working height of only 3m in some cases. To achieve this a Hütte HBR 203 rig, which thanks to its separate diesel power pack is small enough to be able to operate inside the station was employed.
Thanks to the rig's height of 280cm (with the drill mast raised up) it was possible to drill the piles with a diameter of 420 mm while the railway was in operation and directly under the overhead lines and roofs of the station.
Furthermore, the reinforcement cages had to be installed in single sections with sleeves under the restricted height. The prerequisite for carrying out the work is the prequalification of the DB for supporting structures and construction under railway operations.