This stage involves the construction of a curve to the Westhafen and an eastern connection to Wedding inside the northern Ringbahn. Structural preparation for these junctions to these lines had already been made during the construction of the North–South mainline in 2006. From there, the existing line will run in a southerly direction (in the tunnel layer) to the Berlin Hauptbahnhof east of the North–South mainline. The realization of an intermediate station under the working name of "Perleberger Brücke" (as a two-level station in a V-shape) is provided as an option. It was proposed to complete this 1,600-meter-long section by 2016. After construction delays caused by the inflow of groundwater, an opening in summer 2021 has been expected since 2017.