What is "permanent way"

Permanent \Per"ma*nent\, a. [L. permanens, -entis, p. pr. of permanere to stay or remain to the end, to last; per + manere to remain: cf. F. permanent. See Per-, and Mansion.] Continuing in the same state, or without any change that destroys form or character; remaining unaltered or unremoved; abiding; durable; fixed; stable; lasting; as, a permanent impression.

Eternity stands permanent and fixed.
--Dryden.

Permanent gases (Chem. & Physics), hydrogen, oxygen, nitrogen, and carbon monoxide; -- also called incondensible gases or incoercible gases, before their liquefaction in 1877. The term is now archaic.

Permanent way, the roadbed and superstructure of a finished railway; -- so called in distinction from the contractor's temporary way.

Permanent white (Chem.), barium sulphate ( heavy spar), used as a white pigment or paint, in distinction from white lead, which tarnishes and darkens from the formation of the sulphide.

Syn: Lasting; durable; constant. See Lasting.

n. (context rail transport British English) the track and bed of a railway

The permanent way is the elements of railway lines: generally the pairs of rails typically laid on the sleepers ("ties" in American parlance) embedded in ballast, intended to carry the ordinary trains of a railway. It is described as permanent way because in the earlier days of railway construction, contractors often laid a temporary track to transport spoil and materials about the site; when this work was substantially completed, the temporary track was taken up and the permanent way installed.

The earliest tracks consisted of wooden rails on transverse wooden sleepers, which helped maintain the spacing of the rails. Various developments followed, with cast iron plates laid on top of the wooden rails and later wrought iron plates or wrought iron angle plates (L-shaped plate rails). Rails were also individually fixed to rows of stone blocks, without any cross ties to maintain correct separation. This system also led to problems, as the blocks could individually move, and it was replaced by the "modern system" of rails and transverse sleepers. Although, Brunel's broad gauge system used rails laid on longitudinal sleepers tied to piles.

Developments in manufacturing technologies has led to changes to the design, manufacture and installation of rails, sleepers and the means of attachments. Cast iron rails, long, began to be used in the 1790s and by 1820, long wrought iron rails were in use. The first steel rails were made in 1857 and standard rail lengths increased over time from . Rails were typically specified by units of weight per linear length and these also increased. Railway sleepers were traditionally made of Creosote-treated hardwoods and this continued through to modern times. Continuous welded rail was introduced into Britain in the mid 1960s and this was followed by the introduction of concrete sleepers.

Permanent way is the tracks, ballast, subgrade and lineside structure of a railway, see:

• Track (rail transport), description of contemporary permanent way structures and methods
• Permanent way (history), a history of permanent way in the UK

• Permanent Way Institution
• The Permanent Way, a play by David Hare about the privatisation of Britain's railways
• "Permanent way" is an important road in the novel Absolution Gap by Alastair Reynolds