Winter transport goes down line with crew one short (9)
I believe the answer is:
bobsleigh
'winter transport' is the definition.
(I've seen this before)
'goes down line with crew one short' is the wordplay.
'goes down' becomes 'bobs' (bob can mean to go up and down).
'line' becomes 'l'.
'with' means one lot of letters go next to another.
'crew' becomes 'eight' (an eight-person rowing team).
'one short' means to remove the last letter.
'eight' with its last letter removed is 'eigh'.
'bobs'+'l'+'eigh'='BOBSLEIGH'
(Other definitions for bobsleigh that I've seen before include "Vehicle ridden quickly down" , "downhill racer" , "winter sport" , "Winter transport" , "Winter Olympic discipline" .)