Farm transport three feet up (4)
I believe the answer is:
dray
'farm transport' is the definition.
(type of cart)
'three feet up' is the wordplay.
'three feet' becomes 'yard' (I've seen this before).
'up' says the letters should be written backwards (in down clue: letters go upwards).
'yard' written backwards gives 'DRAY'.
(Other definitions for dray that I've seen before include "Cart without sides, for delivering barrels" , "Cart used for heavy loads" , "delivery vehicle" , "Heavy load-carrying vehicle" , "Draught horse" .)