Traveller for half fare, on the quiet (3)
I believe the answer is:
rep
'traveller' is the definition.
(travel company worker)
'half fare on the quiet' is the wordplay.
'half' indicates taking half.
'on' says to put letters next to each other.
'the quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'fare' with half the letters taken is 're'.
're'+'p'='REP'
'for' acts as a link.
(Other definitions for rep that I've seen before include "agent" , "Fabric with a ribbed surface" , "Theatre; fabric; salesman" , "Material for curtains" , "Travelling salesman" .)