The Munich S-Bahn Stammstrecke is an 11.4 km long portion of the Munich S-Bahn, serving as its core segment where all services meet, running from Munich Pasing station to Munich East station, partly running in a double-track 4.343 km rail tunnel connecting München Hauptbahnhof with Munich East station underneath the Altstadt-Lehel and Au-Haidhausen boroughs. Wikipedia