Trainspotter's article artist displayed in fair (6)
I believe the answer is:
anorak
'trainspotter's' is the definition.
(I've seen this before)
'article artist displayed in fair' is the wordplay.
'article' becomes 'an' (indefinite article).
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'displayed in' indicates putting letters inside.
'fair' becomes 'ok'.
'ra' placed within 'ok' is 'orak'.
'an'+'orak'='ANORAK'
(Other definitions for anorak that I've seen before include "Jacket for obsessives?" , "Raincoat" , "trainspotter" , "Protection from the wet" , "Jacket for an obsessive?" .)