Trainee fit to fix elevator (4)
I believe the answer is:
lift
'elevator' is the definition.
(I know that elevator can be written as lift)
'trainee fit to fix' is the wordplay.
'trainee' becomes 'l' (as in an L-plate for a learner driver).
'to fix' is an anagram indicator (I've seen 'fixed' mean this).
'fit' with letters rearranged gives 'ift'.
'l'+'ift'='LIFT'
(Other definitions for lift that I've seen before include "Free ride" , "Raise - hoist" , "Means of access to different floors" , "Raise - shot in the arm" , "It's an elevator in USA" .)