On behalf of Wiener Linien, the operator of the Vienna subway, a joint venture between STRABAG and PORR is building the extension of subway line 2 from Vienna City Hall to the south. The Austrian tunnel construction specialists ordered an EPB Shield (Earth Pressure Balance Shield) tunnel boring machine from Herrenknecht for this project.

Ralph Lickert, project manager at Herrenknecht, said: "The Herrenknecht EPB Shield is the optimal machine type for the predominantly clayey geology that we expect according to the preliminary investigations."

The Herrenknecht EPB Shield for the Austrian capital has a diameter of 6840mm, a length of around 120m and weighs a total of around 1200t.

The drive will start at the future Matzleinsdorfer Platz station, from where the machine will drive 2.1km of tunnel northwards to below Augustinplatz. The machine will then be pulled back through the bored tunnel, which is lined with precast concrete segments, in order to drive the parallel tube from Matzleinsdorfer Platz. 

With the expansion of the metro network, the city of Vienna is responding to a rising population. More than two million people are expected to live in the capital by 2030. According to the city, the investment in the line extensions will create and secure around 30,000 jobs.