"Wien Mitte is a rail and U-Bahn station in Vienna, close to the city centre. It is the city terminus of Vienna's City Airport Train (CAT), which provides non-stop service to Vienna International Airport.[...] The journey to the airport via CAT takes 16 minutes."
"Landstraße U-Bahn station is serviced by both U3 and U4 and has 4 platforms. U4 goes north and south of the station whilst U3 goes west and south-east."
-> Quoted from Wien Mitte Railway Station @ Wikipedia