Some feel Cricklewood's about to get a London Underground line (6)
I believe the answer is:
circle
'a london underground line' is the definition.
(the Circle line on the London Underground)
'some feel cricklewood's about' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'about' says the letters should be written in reverse.
'elcric' can be found hidden inside 'feel cricklewood'.
'elcric' reversed gives 'CIRCLE'.
'to get' acts as a link.
(Other definitions for circle that I've seen before include "Move around (something)" , "Curved closed line" , "Geometric figure" , "Dress -; Magic -" , "Clique; loop" .)