The subterranean Munich S-Bahn station is separated operationally from the mainline station and known as "München Hbf (tief)". To optimise passenger flow, separate platforms for entering (centre) and disembarking (outer) trains exist. This arrangement of platforms is called "Spanish solution". The subway station is situated near the U-Bahn lines for the U1 and U2 trains, but if one wishes to change from the S-Bahn to U4/U5 trains, it is more practical to stay on the S-Bahn to Karlsplatz (Stachus), as the U4/U5 station is on the opposite side of the station.