Английский Этимологический словарь - rail (n.1)

- "bar," late 13c., from O.Fr. reille, from L. regula "straight stick," dim. form related to regere "to straighten, guide" (see right). Technically, railings (1471) are horizontal, palings are vertical. Railroad (n.) is 1757, originally "road laid with rails for heavy wagons;" use for trains is from 1825, though tending to be replaced in this sense in England by railway. The verb meaning "to convict quickly and perhaps unjustly" is from 1884.