railway line vs spur

railway line and spur both are nouns.

Word	Noun	Adjective	Verb	Adverb
railway line	Yes	No	No	No
spur	Yes	No	Yes	No

As nouns, spur is a hyponym of railway line; that is, spur is a word with a more specific, narrower meaning than railway line:

Other hyponyms of railway line include branch line, spur track, trunk line, trunk route.

railway line (noun)	spur (noun)
the road consisting of railroad track and roadbed	a sharp prod fixed to a rider's heel and used to urge a horse onward
line that is the commercial organization responsible for operating a system of transportation for trains that pull passengers or freight	a railway line connected to a trunk line
	a verbalization that encourages you to attempt something
	tubular extension at the base of the corolla in some flowers
	any sharply pointed projection