See drain (anag) — next to the kerb (8)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
nearside
(Other definitions for nearside that I've seen before include "On which one finds passenger" , "passenger should alight here" , "Part of car closest to kerb" , "horseman's left" , "Part of vehicle closest to the kerb" .)