Liquid carried by boat and coach, source of easy money (5,5)
I believe the answer is:
gravy train
'source of easy money' is the definition.
(I've seen this in another clue)
'liquid carried by boat and coach' is the wordplay.
I cannot really understand how this works, but
'liquid' could be 'rain' (rain is a kind of liquid) and 'rain' is present in the answer.
'boat' could be 'gravy' (synonyms) and 'gravy' is found within the answer.
A single letter 't' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for gravy train that I've seen before include "Opportunity to make money" , "Scheme for easy money" , "Situation making easy money (colloq.)" , "easy opportunity of profit" , "Jobs with more perks than work" .)