Rack railway and Railway line

Rack railway noun - Railway for steep mountains; a cogwheel on the locomotive engages cogs on a center rail to provide traction.

Railway line and rack railway are semantically related. In some cases you can use "Railway line" instead a noun phrase "Rack railway".

Railway line noun - Line that is the commercial organization responsible for operating a system of transportation for trains that pull passengers or freight.

Rack railway and railway line are semantically related. Sometimes you can replace phrase "Rack railway" with "Railway line", this phrases are similar.