Long line for food store (6)
I believe the answer is:
pantry
'food store' is the definition.
(I've seen this before)
'long line' is the wordplay.
'long' becomes 'pant' (I've seen this before**).
'line' becomes 'ry' (abbreviation for railway).
'pant'+'ry'='PANTRY'
'for' is the link.
(Other definitions for pantry that I've seen before include "Store cupboard" , "Room off the kitchen" , "Type of larder" , "Food store" , "Kitchen storeroom" .)