Work for press, taking public transport to north (3)
I believe the answer is:
sub
'work for press' is the definition.
(to act as a subeditor)
'public transport to north' is the wordplay.
'public transport' becomes 'bus' (bus is a kind of public transport).
'to north' says the letters should be written backwards.
'bus' written backwards gives 'SUB'.
'taking' is the link.
(Other definitions for sub that I've seen before include "Prefix denoting under" , "Loan" , "Junior editor" , "Prefix meaning under or inferior" , "Beneath on bus" .)