Perks from working in public transport (7)
I believe the answer is:
bonuses
'perks' is the definition.
(I've seen this in another clue)
'working in public transport' is the wordplay.
'working' becomes 'on' (on can mean working or activated).
'in' is an insertion indicator.
'public transport' becomes 'buses' (I've seen this before).
'on' going within 'buses' is 'BONUSES'.
'from' is the link.
(Other definitions for bonuses that I've seen before include "Advantages" , "Extra payments for good work" , "benefits" .)