Nose quietly by railway (3)
I believe the answer is:
pry
'nose' is the definition.
(to nose around is to pry)
'quietly by railway' is the wordplay.
'quietly' becomes 'p' (p for piano and quiet).
'by' says to put letters next to each other.
'railway' becomes 'ry' (abbreviation for railway).
'p'+'ry'='PRY'
(Other definitions for pry that I've seen before include "Snoop or lever" , "Enquire too inquisitively" , "Peer impertinently, stick nose in" , "Be nosy" , "Look inquisitively into private matters" .)