1. route (bus, train, air, etc.); line
桜井たちが住んでいる付近にはバスの路線がない。There are no bus routes in the area where Sakurai and the others live.
2. line (taken by a group, organization, etc.); policy; course
あえてこの路線で話を進めてみる。I will deliberately try to proceed with the discussion along this line.