slip coach vs railway car

slip coach and railway car both are nouns.

Word	Noun	Adjective	Verb	Adverb
slip coach	Yes	No	No	No
railway car	Yes	No	No	No

As nouns, railway car is a hypernym of slip coach; that is, railway car 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
railway car: a wheeled vehicle adapted to the rails of railroad

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

slip coach (noun)	railway car (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