Raised section in carriage (4)
I believe the answer is:
trap
'carriage' is the definition.
(trap is a kind of carriage)
'raised section' is the wordplay.
'raised' is a reversal indicator (going up in a down clue).
'section' becomes 'part' (synonyms).
'part' back-to-front is 'TRAP'.
'in' is the link.
(Other definitions for trap that I've seen before include "Baited device" , "Control ball" , "Means of transport - sometimes sprung!" , "Ambush" , "Driver's obstacle" .)