noun, noun which may take the genitive case particle 'no'
main line; trunk line
Refers to a primary route or artery in transportation (railways, roads) or utility networks (power, water, gas). Often used attributively with の.
この道路は市の幹線道路です。
This road is a main artery of the city.
幹線鉄道が大雪で止まった。
The main railway line was stopped by heavy snow.