slip carriage vs railcar

slip carriage and railcar both are nouns.

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

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

slip carriage: 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 carriage include car, railroad car, railway car.

slip carriage (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