And just for another comparison: The MVV (Munich Transport and Tariff Association / Muenchner Verkehrsverbund) serves 2.6 million people (Munich and the greater Munich Area). The S-Bahn (commuter trains) lines are 442 km, the subway lines 103 km and the tramway is 75 km. There is also the bus with 457 km on 66 lines in the city.
(I've ignored buses for the outer regions and the option to use trains to reach the city from suburbs).