State noble line (7)
I believe the answer is:
country
'state' is the definition.
(I know that state can be written as country)
'noble line' is the wordplay.
'noble' becomes 'count' (count is a type of aristocrat).
'line' becomes 'ry' (abbreviation for railway).
'count'+'ry'='COUNTRY'
(Other definitions for country that I've seen before include "Rural" , "land?" , "See 9" , "Nation" , "State; region" .)