History of the railway track

The railway track or permanent way is the elements of railway lines: generally the pairs of rails typically laid on the sleepers or ties embedded in ballast, intended to carry the ordinary trains of a railway. It is described as a 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 (angle iron as 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. The first version of Isambard Kingdom Brunel's 7 ft (2,134 mm) broad gauge system used rails laid on longitudinal sleepers whose rail gauge and elevation were pinned down by being tied to piles (conceptually akin to a pile bridge), but this arrangement was expensive and Brunel soon replaced it with what became the classic broad gauge track, in which the piles were forgone and transoms, similar to sleepers, maintained the rail gauge. Today, most rail track uses the standard system of rail and sleepers; ladder track is used in a few applications. 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, 4 feet (1.2 m) long, began to be used in the 1790s and by 1820, 15-foot-long (4.6 m) wrought iron rails were in use. The first steel rails were made in 1857 and standard rail lengths increased over time from 30 to 60 feet (9.1–18.3 m). 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.

Wooden tracked systems

Plank ways

The earliest use of a railway track seems to have been in connection with mining in Germany in the 12th century. Mine passageways were usually wet and muddy, and moving barrows of ore along them was extremely difficult. Improvements were made by laying timber planks so that wheeled containers could be dragged along by manpower. By the 16th century, the difficulty of keeping the wagon running straight had been solved by having a pin going into a gap between the planks. Georg Agricola describes box-shaped carts, called "dogs", about half as large again as a wheelbarrow, fitted with a blunt vertical pin and wooden rollers running on iron axles. An Elizabethan era example of this has been discovered at Silvergill in Cumbria, England, and they were probably also in use in the nearby Mines Royal of Grasmere, Newlands and Caldbeck. Where space permitted round-section wooden tracks to take trucks with flanged wheels were installed: a painting from 1544 by the Flemish artist Lucas Gassel shows a coppermine with rails of this type emerging from an adit.

Edged rails

A different system was developed in England, probably in the late 16th century, near Broseley for conveying coal from mines, sometimes drift mines down the side of the Severn Gorge to the River Severn. This, probably a rope-hauled incline plane, had existed 'long before' 1605. This probably preceded the Wollaton Wagonway of 1604, which has hitherto been regarded as the first. In Shropshire, the gauge was usually narrow, to enable the wagons to be taken underground in drift mines. However, by far the greatest number of wagonways were near Newcastle upon Tyne, where a single wagon was hauled by a horse on a wagonway of about the modern standard gauge. These took coal from the pithead down to a staithe, where the coal was loaded into river boats called keels. Wear of the timber rails was a problem. They could be renewed by turning them over, but had to be regularly replaced. Sometimes, the rail was made in two parts, so that the top portion could easily be replaced when worn out. The rails were held together by wooden sleepers, covered with ballast to provide a surface for the horse to walk on.

Early iron rails Cast iron strips could be laid on top of timber rails, and the use of such materials probably occurred in 1738, but there are claims that this technology went back to 1716. In 1767, Ketley ironworks began producing cast iron plates, which were fixed to the top of wooden rails with nails, to provide a more durable running surface. This construct was known as strap-iron rail (or strap rail) and was widely used on pre-steam railways in the United States. Although relatively cheap and quick to build, they were unsuited to heavy loads and required 'excessive maintenance'. Train wheels rolling over the spikes loosened them, allowing the rail to break free and curve upwards sufficiently that a car wheel could get beneath it and force the end of the rail up through the floor of the car, writhing and twisting, endangering passengers. These broken rails became known as "snake heads". When wrought iron became available, wrought iron plates provided an even more durable surface. The rails had projecting lugs (or ears) with a hole to enable them to be fixed to the underlying wooden rail.

Iron plateways

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