rack railway vs railway system

rack railway and railway system both are nouns.

Word	Noun	Adjective	Verb	Adverb
rack railway	Yes	No	No	No
railway system	Yes	No	No	No

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

rack railway: railway for steep mountains; a cogwheel on the locomotive engages cogs on a center rail to provide traction
railway system: line that is the commercial organization responsible for operating a system of transportation for trains that pull passengers or freight

Other hypernyms of rack railway include railroad, railroad line, railway, railway line.

rack railway (noun)	railway system (noun)
railway for steep mountains; a cogwheel on the locomotive engages cogs on a center rail to provide traction	line that is the commercial organization responsible for operating a system of transportation for trains that pull passengers or freight