(motor racing) The most optimal (fastest) line or course on a track.

Marked by blue lines.

(fishing) A fishing line that is not wound on a reel.

plural of rod line

plural of line speed

(rail transport) The maximum speed at which trains can run on a given railway line, or section of line.

plural of running line

present participle of run lines

(rail transport) A railway line used to operate trains on, as opposed to a siding.

Synonym of cash on the barrelhead / Cash that is on hand for any expenses. / Used other than figuratively or idiomatically: see cash, on the line.