Trench for the new Wehrhahn-Linie; photo from 2008
The current Stadtbahn expansion project under construction is a new tunnel from the Düsseldorf-Bilk station in the south of the city to the Düsseldorf-Wehrhahn station. The name of this new underground route is Wehrhahn-Linie. This 3.5 kilometres (2.2 mi) tunnel is projected to be completed in 2015. As with every other underground line opened previously in Düsseldorf, the "Wehrhahn-Linie" will be a replacement for surface tram lines, with current tram lines 703, 712 and 713 expected to be replaced with Stadtbahn service. With completion of the project, trams on this line will enter the new tunnel over a ramp at Bilk railway station and run from there underneath the city centre towards the north-east, where they will emerge shortly before Wehrhahn railway station. Five new underground stations are under construction for the new line, which will serve a daily passenger volume of approximately 53,000.