Brenner's Gearing Up

In this article the author discusses improvements to the Lower Inn Valley section of the continuous rail connection currently being built to connect Berlin, Germany, to Palermo, Italy. The Lower Inn Valley project, located in Brenner, Austria will require $2.9 billion in funding and will be 40 kilometers long and mostly comprised of excavated tunnels. Nearly half the tunnel will be under high groundwater and will require slurry tunnel boring machine (TBM) drives, subaqueous open-cut excavation, and the jet-piled support of open-face tunnel work. The project also employs the slightly older technique of using a single tube with double tracking. The open face tunnels are supported with a combination of shotcrete and rockbolts, drained PVC membrane waterproofing, dowels, and lattice girders and wire mesh. The most complex section of the tunnel involved a subsurface alignment that ran directly in line beneath a highway. The project, while requiring a revised completion date, is on schedule for completion in 2012.