Restrict a railway line (8)

I believe the answer is:

boundary

'line' is the definition.
(I know that boundary is a type of line)

'restrict a railway' is the wordplay.
'restrict' becomes 'bound' (synonyms).
'railway' becomes 'ry' (abbreviation for railway).
'bound'+'a'+'ry'='BOUNDARY'

(Other definitions for boundary that I've seen before include "Limit (of an area)" , "Border (especially in cricket)" , "march" , "Limit; hit at cricket" , "Perimeter: demarcation" .)

I've seen this clue in The Telegraph.

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