Trains with carriages (7)
I believe the answer is:
coaches
This clue is a double definition.
'trains' is the first definition.
(I know this)
'carriages' is the second definition.
(I know this)
'with' acts as a link.
(Other definitions for coaches that I've seen before include "People carriers and trainers" , "Buses, carriages" , "Instructors in sports" , "Trainers or buses" , "Trainers for athletes or transport vehicles" .)