Rail car riotous with sailors into drink (9)
I believe the answer is:
corncrake
'rail' is the definition.
(corncrake is a kind of rail)
'car riotous with sailors into drink' is the wordplay.
'riotous' indicates anagramming the letters.
'with' is a charade indicator (letters next to each other).
'sailors' becomes 'rn' (abbreviation for Royal Navy).
'into' is an insertion indicator.
'drink' becomes 'coke' (Coke is an example**).
'car' with letters rearranged gives 'cra'.
'cra' after 'rn' is 'rncra'.
'rncra' put within 'coke' is 'CORNCRAKE'.
(Other definitions for corncrake that I've seen before include "kind of rail" , "Bird" .)