Transport by car and railway (5)
I believe the answer is:
carry
'transport' is the definition.
(I know that transport can be written as carry)
'car and railway' is the wordplay.
'and' means one lot of letters go next to another.
'railway' becomes 'ry' (abbreviation).
'car'+'ry'='CARRY'
'by' is the link.
(Other definitions for carry that I've seen before include "Bring" , "Be pregnant (with)" , "Transport, fetch" , "Transport; transmit" , "(Of sound) be audible at a distance" .)