dining compartment vs buffet car

dining compartment and buffet car both are nouns.

Word	Noun	Adjective	Verb	Adverb
dining compartment	Yes	No	No	No
buffet car	Yes	No	No	No

As nouns, dining compartment and buffet car are synonyms defined as:

dining compartment and buffet car: a passenger car where food is served in transit

Other synonyms of dining compartment include diner, dining car.

dining compartment (noun)	buffet car (noun)
a passenger car where food is served in transit	a passenger car where food is served in transit