With around 840 000 passengers per day, the Munich S-Bahn is one of the largest public transport systems in Germany. Opened as early as 1972 for the Olympic Games, the 11.3 km long main line has reached its capacity limit, as all S-Bahn trains have to pass under Munich city center through a tunnel. This problem is now being tackled by the construction of the approximately 10 km long 2nd main line. The article in tunnel 5/2023 presents the eastern part, award unit 733 with the tunnel from Marienhof up to and including deep-level East Station, (Ostbahnhof tief). The tender is expected to be issued by the end of 2023.