No railway covering the start of route towards the Arctic (9)
I believe the answer is:
northerly
'arctic' is the definition.
(thesaurus)
'no railway covering the start of route towards the' is the wordplay.
'railway' becomes 'rly' ().
'covering' is an insertion indicator.
'the start of' says to take the initial letters.
'towards' means one lot of letters go next to another (I've seen this in other clues).
The first letter of 'route' is 'r'.
'no'+'rly'='norly'
'r'+'the'='rthe'
'norly' placed around 'rthe' is 'NORTHERLY'.
(Other definitions for northerly that I've seen before include "From cold parts" , "it may be a bitter blow" , "Wind blowing south" , "like Newcastle?" .)