Buffet cars inter alia currently serving rich gravy (7,5)
I believe the answer is:
rolling stock
'buffet cars inter alia currently' is the definition.
I can't tell whether this defines the answer.
'rich gravy' is the wordplay.
'rich' becomes 'rolling' (rolling in it).
'gravy' becomes 'stock' (I can't explain this - if you can you should give a lot more credence to this answer).
'rolling'+'stock'='ROLLING-STOCK'
'serving' acts as a link.
Can you help me to learn more?
(Other definitions for rolling stock that I've seen before include "Railway wagons" , "Railway vehicles" , "Rail vehicles" , "Locomotives and coaches" , "Locomotives, carriages etc" .)