Bent on going west on the railway (3)
I believe the answer is:
wry
'bent' is the definition.
(thesaurus)
'on going west on the railway' is the wordplay.
'going' is a deletion indicator.
'west' becomes 'W' (abbreviation).
'the railway' becomes 'ry' (abbreviation for railway).
'w'+'on'+'ry'='wonry'
'wonry' with 'on' taken out is 'WRY'.
(Other definitions for wry that I've seen before include "Of humour, dry and mocking" , "Dry and mocking, or bent out of shape" , "Drily humorous" , "Twisted; sardonic" , "Ironically humorous" .)