Unwilling to move train sets (9)
I believe the answer is:
resistant
'unwilling' is the definition.
(thesaurus)
'to move train sets' is the wordplay.
'to move' indicates anagramming the letters (I've seen 'moving' mean this).
'train'+'sets'='trainsets'
'trainsets' with letters rearranged gives 'RESISTANT'.
(Other definitions for resistant that I've seen before include "(Of germs) withstanding treatment" , "Unyielding - proof" , "Rebel" , "Impervious (to corrosion, heat, etc)" , "Impervious to various sources of damage" .)