branch line vs railway line

branch line and railway line both are nouns.

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

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

Other hypernyms of branch line include line, rail line.

branch line (noun)	railway line (noun)
a railway line connected to a trunk line	the road consisting of railroad track and roadbed
	line that is the commercial organization responsible for operating a system of transportation for trains that pull passengers or freight