Some more advice: If you are on a tight connection at central station, be sure to board the S-Bahn train in the first coach. Upon getting off at central station, walk in the direction of travel and take the flight of stairs at the very end of the S-Bahn station. After a right U-turn (and another flight of stairs), you'll end up somewhere between tracks 1 and 2 (of 16) in the station.