幹線

main line / trunk line

tree trunk / main part of sth / to manage / to work / to do / capable / cadre / to kill (slang) / to fuck (vulgar) / (coll.) pissed off / annoyed

thread / string / wire / line / CL:條|条[tiao2],股[gu3],根[gen1] / (after a number) tier (unofficial ranking of a Chinese city)

Shinkansen (Japanese high-speed train)

trunk line (of road, network etc) / backbone (cable)