cabin car vs railcar

cabin car and railcar both are nouns.

Word	Noun	Adjective	Verb	Adverb
cabin car	Yes	No	No	No
railcar	Yes	No	No	No

As nouns, railcar is a hypernym of cabin car; that is, railcar is a word with a broader meaning than cabin car:

cabin car: a car on a freight train for use of the train crew; usually the last car on the train
railcar: a wheeled vehicle adapted to the rails of railroad

Other hypernyms of cabin car include car, railroad car, railway car.

cabin car (noun)	railcar (noun)
a car on a freight train for use of the train crew; usually the last car on the train	a wheeled vehicle adapted to the rails of railroad