Tough pasture north of the railway (8)
I believe the answer is:
leathery
'tough' is the definition.
(similar in meaning)
'pasture north of the railway' is the wordplay.
'pasture' becomes 'lea' (both can mean a field).
'north of' is a charade indicator (letters next to each other) (in a down clue, some letters go above others).
'railway' becomes 'ry' (abbreviation for railway).
'lea'+'the'+'ry'='LEATHERY'
(Other definitions for leathery that I've seen before include "rather tough" , "Like a football" , "Tough (meat, hide)" , "like old boots?" , "Like tough skin" .)