Carthorse transported musicians (9)
I believe the answer is:
orchestra
'musicians' is the definition.
(I've seen this before)
'carthorse transported' is the wordplay.
'transported' indicates anagramming the letters.
'carthorse' with letters rearranged gives 'ORCHESTRA'.
(Other definitions for orchestra that I've seen before include "Big band" , "Group of musical instrumentalists" , "Carthorse (anag)" , "Gamelan, for instance" , "Large body of musicians" .)