Reichsbahn, the project was called "S-Bahn" for the first time. Due to World War II the construction and plans for the Munich S-Bahn were set aside. Plans, with the Munich Olympic bid In 1965, the Federal Republic of Germany, the Free State of Bavaria, the state capital of Munich and the Deutsche Bundesbahn signed a contract on the construction of the Munich S-Bahn. The further development was most influenced by a decision made in Rome on 26 April 1966: the International Olympic Committee chose Munich over Detroit, Madrid and Montreal as the location for the 1972 Summer Olympics, resulting in a tight schedule of only six years to complete the Munich S-Bahn network. Not only did the tunnel through the city centre have to be built, the full railway infrastructure had to be expanded. The network of suburban lines had to be changed over and modernized. A large number of stations had to be upgraded; platforms were extended to a length of to allow for three-unit trains, and the platform height was raised to . However, the floor height of trains used then and now is at approximately , which makes boarding difficult for people with wheelchairs or prams. Tunnel stations and platforms updated recently where no freight trains run do feature a height of , however. On 25 February 1971 the topping-out ceremony could be celebrated in the core route tunnel. In May the first S-Bahn train of the ET 420 series was put into service on the route between Pasing and Gauting. On 1 September 1971 a regular advance service was started on that route. Opening On 28 May 1972, the Munich S-Bahn network was finally put into service with of tracks and 101 trains of the ET 420 series. Town names in the nearby Munich such as Dachau, Tutzing, Erding and Pasing came into the picture. It was the first time a S-Bahn network that size was put into service on a single date. The route S10 to Wolfratshausen (today S7) was operated with conventional push-pull trains from the southern wing of Munich Central Station. It was electrified later and connected to the core route after the construction of a tunnel crossing the large number of mainline rail tracks leading to Munich Central Station. Three months later the German President Gustav Heinemann opened the 1972 Summer Olympics. During the Games there were two additional S-Bahn lines servicing