slip coach vs railcar

slip coach and railcar both are nouns.

Word	Noun	Adjective	Verb	Adverb
slip coach	Yes	No	No	No
railcar	Yes	No	No	No

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

slip coach: a railway car at the end of the train; it can be detached without stopping the train
railcar: a wheeled vehicle adapted to the rails of railroad

Other hypernyms of slip coach include car, railroad car, railway car.

slip coach (noun)	railcar (noun)
a railway car at the end of the train; it can be detached without stopping the train	a wheeled vehicle adapted to the rails of railroad