Services on the Berlin S-Bahn were at first provided by the German national railway, the Deutsche Reichsbahn. Electrification of the existing suburban lines was completed around 1929, and thoughts turned to a new project: a tunnel that would join two spur lines that protruded into the city centre from the north and south. This tunnel, to be known as the Nord-Süd-Bahn, was a prestige project for the Nazis, and was opened in two sections. The first, from the north to Unter den Linden, opened in time for the 1936 Berlin Olympics; the final section, via Potsdamer Platz, opened the month after the Second World War began, in October 1939.
During and after World War II
Some Type 477 trains, built before World War II, remained in service until the early 21st century
Many sections of the S-Bahn were closed during the war due to enemy action. The Nord-Süd-Bahn tunnel was flooded on 2 May 1945 by retreating SS troops during the final Battle of Berlin[citation needed]. The exact number of casualties is not known, but up to 200 people are presumed to have perished. $325.00
