The extension of Line C of the Berlin U-Bahn (today called U6) through the centre of Tempelhof to Mariendorf was already planned before World War II, and was begun in the late 1930s. A tunnel was dug south from the turnaround at Tempelhof station almost to the location of the Alt-Tempelhof station, and a somewhat longer tunnel section was also dug further south, between today's Alt-Tempelhof and Kaiserin-Augusta-Straße stations.
The expansion of Line C of the Berlin U-Bahn (now called U6) through the heart of Tempelhof to Mariendorf was already planned before World War II, and construction began in the late 1930s. A tunnel was dug south from the turnaround at Tempelhof station almost to the location of the Alt-Tempelhof station, and a somewhat longer tunnel section was also dug further south, between today's Alt-Tempelhof and Kaiserin-Augusta-Straße stations.