None of the planned U2/U5 routes will be elevated, largely because the urban area above is far too dense.
It was possible to have parts of the U1, U2 and U3 underground lines run long elevated sections.
A construction highlight was achieved during the work to extend the U2 towards Seestadt: the incremental launching technique was used for the first time in Vienna when crossing the ÖBB railway station Stadlau and the A23 motorway.
This technique involved putting together precast steel bridge sections on an assembly platform and sliding them forwards on to previously erected bridge pillars, section by section, using hydraulic presses.
