More proficient part of cable railway (5)
I believe the answer is:
abler
'more proficient' is the definition.
(I've seen this in another clue)
'part of cable railway' is the wordplay.
'part of' indicates the answer is hidden within the clue.
'ABLER' can be found hidden inside 'cable railway'.
(Other definitions for abler that I've seen before include "fitter" , "The better" , "Increasingly smart" , "More proficient" , "More capable" .)