Go by car or train (4)
I believe the answer is:
ride
This clue is a double definition.
'go by car' is the first definition.
(I've seen this in another clue)
'train' is the second definition.
(I know this)
(Other definitions for ride that I've seen before include "Journey as passenger" , "Travel, by horse say" , "Sit on (a horse/vehicle)" , "Take journey" , "Fairground entertainment" .)