road vs railway line

road and railway line both are nouns.

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

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

road (noun)	railway line (noun)
a way or means to achieve something	the road consisting of railroad track and roadbed
an open way (generally public) for travel or transportation	line that is the commercial organization responsible for operating a system of transportation for trains that pull passengers or freight