The 32.8 km long Koralm Tunnel in Kärnten and Styria will be the longest rail tunnel in Austria, representing the core of the 130 km long, twin-track Koralmbahn Graz-Klagenfurt, currently under construction. This high-speed route (200 km/h) involves total investments in excess of € 5 billion. It provides the main link between the Baltic and the Adriatic (TEN Corridor 23) and is a central project of Austria’s infrastructural development. After concluding prior investigations (Leibenfeld, Peierdorf and Mitterpichling exploratory tunnels and the Peierdorf exploratory shaft) and the granting of the building permit in late 2007, work began on the 2 tunnel bores in 2011 with the roughwork due for completion in 2018.
The 2 tunnel bores for the Koralm Tunnel with a centre distance of roughly 40 m are linked every 500 m by cross-passages with a more than 900 m long emergency stop foreseen at the centre of the tunnel. The altogether 32.8 km long tunnel is split into 3 sections, with the roughly 19 km long central contract section KAT2 the longest one: the 2 parallel single-track bores with an excavated cross-section of some 82 m² are to driven by mechanised means with tunnelling machines towards Kärnten mainly through crystalline rock (glimmer slate, gneisses etc.) by 2016 (30 m/day). The tunnel bores of contract section KAT1 (4.1/5.1 km) are driven cyclically (NATM) from the Leibenfeld ventilation shaft and those of contract section KAT3 (roughly 11 km) either mechanically or cyclically.⇥G.B.