The stations Hauptbahnhof ( Central Station ) ( U1\/U2 ) and MÃ 1\/4 nchner Freiheit ( U3\/U6 ) have four tracks . Central Station ( lower level ) ( Hauptbahnhof unten ) , where U1 and U2 branch into two different lines and MÃ 1\/4 nchner Freiheit ( U3\/U6 ) also have four tracks .