 On 15 May 1933, the long-distance trunk line between Berlin and Zehlendorf was also electrified.This allowed the so-called "banker trains " of the S-Bahn from the Wannsee line to change at Zehlendorf to the trunk line and then run without stopping until Potsdam station.In addition electric railcars operating on the long-distance lines continued as steam hauled suburban trains along the direct route to Potsdam without going through Wannsee.