coach vs railway car

coach and railway car both are nouns.

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

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

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

coach (noun)	railway car (noun)
a carriage pulled by four horses with one driver	a wheeled vehicle adapted to the rails of railroad
a railcar where passengers ride
a vehicle carrying many passengers; used for public transport
a person who gives private instruction (as in singing, acting, etc.)
(sports) someone in charge of training an athlete or a team

coach (verb)	railway car (verb)
teach and supervise (someone); act as a trainer or coach (to), as in sports
drive or operate a coach or carriage