SERVICES
Polyzomba Rail Contractors offers a range of services, including turnkey solutions and the construction and maintenance of rail and related services.
Civil Works:
- stormwater drainage structures;
- earthworks;
- rail track formation;
- fencing;
- building structures;
Rail Trackwork:
- turnout replacement, incl. VAE 1 : 20, 60kg/m, New Generation Swingnose Sets;
- track welding using electrothermit processes;
- rail handling, new and re-usable;
- sleeper and fastening replacement;
- rail repairs, including skidmarks;
- general track maintenance works, including inspections, localised geometry corrections & spot tamping;
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.
Plank ways
The earliest use of a railway track seems to have been in connection with mining in Germany in the 12th century.[2] 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.[3] 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.[4] An Elizabethan era example of this has been discovered at Silvergill in Cumbria, England,[5] and they were probably also in use in the nearby Mines Royal of Grasmere, Newlands and Caldbeck.[6] 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.[7]
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.[8] This probably preceded the Wollaton Wagonway of 1604, which has hitherto been regarded as the first.[9][10]
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 what was loaded into river boats called keels.[11]
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 sleepers, covered with ballast to provide a surface for the horse to walk on.
Early iron rails
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.[12][13] 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”.[13]
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
Section of L-shaped plate rails
A long fish bellied rail supported over several chairs
An alternative, developed by John Curr of Sheffield, the manager of the Duke of Norfolk‘s colliery there. This had a L-shaped rail, so that the flange was on the rail rather than on the wheel. This was also used by Benjamin Outram of Butterley Ironworks and William Jessop (who became a partner in them in 1790). These were used to transport goods for relatively short distances down to canals, though Curr’s ran between the manor colliery and Sheffield town. These rails are referred to as plates, and the railway is sometimes called a plateway. The term “platelayer” also derives from this origin. In theory, the unflanged wheels could have been used on ordinary highways, but in practice this was probably rarely done, because the wagon wheels were so narrow that they would have dug into the road surface.
The system found wide adoption in Britain. Often, the plates were mounted on stone blocks, and sometimes without sleepers, but that was liable to cause the rails to spread apart, increasing the gauge. Railways of this kind were widely used in south Wales. In particular to transport limestone down to ironworks, and then iron from the ironworks to a canal, sometimes several miles away, to take the products to market. The rails were at first made of cast iron in lengths of typically three feet, spanning between stone blocks.[14]
The stone blocks had been assumed to be permanent, but experience quickly showed that they settled and gradually moved under traffic, creating chaotic track geometry and causing derailments. Another problem was that the running surface was liable to become obstructed by stones, displaced from the ballast. An alternative was to use an iron tie bar to keep the rails to the proper gauge, incorporating a shoe in which the rail was fixed.[14]
An example of this was the Penydarren or Merthyr tramway. This was used by Richard Trevithick to demonstrate a pioneer locomotive in 1804, using one of his high pressure steam engines, but the engine was so heavy that it broke many of the rails.
Early edge rails
Cast iron edge rails were used by Thomas Dadford junior when building the Beaufort and Blaenavon lines to the Monmouthshire canal in 1793. These were rectangular, 2½ inches in width with a depth of 3 inches and 4 feet in length, and required flanges on the wagon wheels. The same year Benjamin Outram used edge rails on the Cromford Canal. T-shaped beams were used by William Jessop on theLoughborough-Nanpanton line in 1794, and his sons used I-shaped beams in 1813–15 on a railway from Grantham to Belvoir Castle. Samples of these rails are held in the Science Museum, London.[15]
A short-lived alternative was the fish-bellied profile, first used by Thomas Barnes (1765–1801) at Walker Colliery, near Newcastle in 1798, which enabled rails to have a longer span between blocks. These were T-section edge rails, three feet long and laid on transverse stone sleepers. These were still made of cast iron.[16]
Post courtesy of Wikipedia: