Koralm Railway: Final Drive

The start of excavation for the Koralm Railway’s Untersammelsdorf Tunnel in Carinthia, Austria, took place on July 7, 2017. According to Klaus Berger, ÖBB’s project manager, the last of six tunnels in the section between Mittlern and Althofen/Drau will present the greatest technical challenge of the entire Koralm Railway. The geological situation is tricky as the 665 m long Untersammelsdorf Tunnel is largely located in fine grained subsoil known as sea clay. Layers of glacial drift and moraine are to be found below the sea clay, until the solid bedrock consisting of phyllite is encountered....