Transport was miserable (5)
I believe the answer is:
moped
This clue is a double definition.
'transport' is the first definition.
(moped is a kind of transport)
'miserable' is the second definition.
(I've seen this before)
'was' acts as a link.
(Other definitions for moped that I've seen before include "Vehicle - sulked" , "Was miserable; a vehicle" , "Wandered about listlessly" , "Light motor cycle" , "Brooded, hung about" .)