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 on Goethestraße, passing through Steintor – Hauptbahnhof/ZOB – Berliner Allee – Sallstraße and ending at Bahnhof Bismarckstraße. It would then resurface at a ramp on Lindemannallee and continue to Bischofsholer Damm.