Bear’s track behind vehicle (5)
I believe the answer is:
carry
'bear's' is the definition.
(bear can mean to carry)
'track behind vehicle' is the wordplay.
'track' becomes 'ry' (abbreviation for railway).
'behind' is a charade indicator (letters next to each other).
'vehicle' becomes 'car' (car is a kind of vehicle).
'ry' put after 'car' is 'CARRY'.
(Other definitions for carry that I've seen before include "Bear, tote" , "Transport; bear" , "Move" , "Bring" , "Transport, fetch" .)