The city centre tunnel for the D line was originally supposed to run from a ramp at Goethestraße via Steintor – Hauptbahnhof/ZOB – Berliner Allee – Sallstraße to Bahnhof Bismarckstraße, resurface on a ramp at Lindemannallee and continue to Bischofsholer Damm.
The city centre tunnel for the D line was initially planned to start at a ramp near Goethestraße, traverse Steintor – Hauptbahnhof/ZOB – Berliner Allee – Sallstraße, and end at Bahnhof Bismarckstraße. It would then resurface on a ramp at Lindemannallee and continue to Bischofsholer Damm.