What are railroad standard sizes?

Railway track gauge (1435 mm)

A standard-gauge railway is a railway with a track gauge of 1,435 mm (4 ft 8+1⁄2 in). The standard gauge is also called Stephenson gauge (after George Stephenson), international gauge, UIC gauge, uniform gauge, normal gauge and European gauge in Europe,[1][2][3][4][5] and SGR in East Africa. It is the most widely used track gauge around the world, with about 55% of the lines in the world using it.

All high-speed rail lines use standard gauge except those in Russia, Finland, and Uzbekistan. The distance between the inside edges of the rails is defined to be 1,435 mm except in the United States, Canada, and on some heritage British lines, where it is defined in U.S. customary/Imperial units as exactly "four feet eight and one half inches",[6] which is equivalent to 1,435.1 mm.

History

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As railways developed and expanded, one of the key issues was the track gauge (the distance, or width, between the inner sides of the rails) to be used. Different railways used different gauges, and where rails of different gauge met – a "gauge break" – loads had to be unloaded from one set of rail cars and reloaded onto another, a time-consuming and expensive process. The result was the adoption throughout a large part of the world of a "standard gauge" of 1,435 mm (4 ft 8+1⁄2 in), allowing interconnectivity and interoperability.

Origins

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A popular legend that has circulated since at least 1937[7] traces the origin of the 1,435 mm (4 ft 8+1⁄2 in) gauge even further back than the coalfields of northern England, pointing to the evidence of rutted roads marked by chariot wheels dating from the Roman Empire.[a][8] Snopes categorised this legend as "false", but commented, that it "is perhaps more fairly labeled as "Partly true, but for trivial and unremarkable reasons".[9] The historical tendency to place the wheels of horse-drawn vehicles around 5 ft (1,524 mm) apart probably derives from the width needed to fit a carthorse in between the shafts.[9] Research, however, has been undertaken to support the hypothesis that "the origin of the standard gauge of the railway might result from an interval of wheel ruts of prehistoric ancient carriages".[10][better source needed]

In addition, while road-travelling vehicles are typically measured from the outermost portions of the wheel rims, it became apparent that for vehicles travelling on rails, having main wheel flanges that fit inside the rails is better, thus the minimum distance between the wheels (and, by extension, the inside faces of the rail heads) was the important one.

A standard gauge for horse railways never existed, but rough groupings were used; in the north of England none was less than 4 ft (1,219 mm). Wylam colliery's system, built before 1763, was 5 ft (1,524 mm), as was John Blenkinsop's Middleton Railway; the old 4 ft (1,219 mm) plateway was relaid to 5 ft (1,524 mm) so that Blenkinsop's engine could be used. Others were 4 ft 4 in (1,321 mm) (in Beamish) or 4 ft 7+1⁄2 in (1,410 mm) (in Bigges Main (in Wallsend), Kenton, and Coxlodge).[12]

English railway pioneer George Stephenson spent much of his early engineering career working for the coal mines of County Durham. He favoured 4 ft 8 in (1,422 mm) for wagonways in Northumberland and Durham, and used it on his Killingworth line. The Hetton and Springwell wagonways also used this gauge.

Stephenson's Stockton and Darlington railway (S&DR) was built primarily to transport coal from mines near Shildon to the port at Stockton-on-Tees. Opening in 1825, the initial gauge of 4 ft 8 in (1,422 mm) was set to accommodate the existing gauge of hundreds of horse-drawn chaldron wagons[13] that were already in use on the wagonways in the mines. The railway used this gauge for 15 years before a change was made, debuting around 1850, to the 1,435 mm (4 ft 8+1⁄2 in) gauge.[page needed] The historic Mount Washington Cog Railway, the world's first mountain-climbing rack railway, is still in operation in the 21st century, and has used the earlier 4 ft 8 in (1,422 mm) gauge since its inauguration in 1868.

George Stephenson introduced the 1,435 mm (4 ft 8+1⁄2 in) gauge (including a belated extra 1⁄2 in (13 mm) of free movement to reduce binding on curves ) for the Liverpool and Manchester Railway, authorised in 1826 and opened 30 September 1830. The extra half inch was not regarded at first as very significant, and some early trains ran on both gauges daily without compromising safety.[16]

The success of this project led to Stephenson and his son Robert being employed to engineer several other larger railway projects. Thus the 4 ft 8+1⁄2 in (1,435 mm) gauge became widespread and dominant in Britain. Robert was reported to have said that if he had had a second chance to choose a gauge, he would have chosen one wider than 4 ft 8+1⁄2 in (1,435 mm).[17][18] "I would take a few inches more, but a very few".[19]

During the "gauge war" with the Great Western Railway, standard gauge was called "narrow gauge", in contrast to the Great Western's 7 ft 1⁄4 in (2,140 mm) broad gauge. The modern use of the term "narrow gauge" for gauges less than standard did not arise for many years, until the first such locomotive-hauled passenger railway, the Ffestiniog Railway was built.[citation needed]

Adoption

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In 1845, in the United Kingdom of Great Britain and Ireland, a Royal Commission on Railway Gauges reported in favour of a standard gauge. The subsequent Gauge Act ruled that new passenger-carrying railways in Great Britain should be built to a standard gauge of 4 ft 8+1⁄2 in (1,435 mm), and those in Ireland to a new standard gauge of 5 ft 3 in (1,600 mm). In Great Britain, Stephenson's gauge was chosen on the grounds that existing lines of this gauge were eight times longer than those of the rival 7 ft or 2,134 mm (later 7 ft 1⁄4 in or 2,140 mm) gauge adopted principally by the Great Western Railway. It allowed the broad-gauge companies in Great Britain to continue with their tracks and expand their networks within the "Limits of Deviation" and the exceptions defined in the Act.

After an intervening period of mixed-gauge operation (tracks were laid with three rails), the Great Western Railway finally completed the conversion of its network to standard gauge in 1892. In North East England, some early lines in colliery (coal mining) areas were 4 ft 8 in (1,422 mm), while in Scotland some early lines were 4 ft 6 in (1,372 mm). The British gauges converged starting from 1846 as the advantages of equipment interchange became increasingly apparent. By the 1890s, the entire network was converted to standard gauge.

The Royal Commission made no comment about small lines narrower than standard gauge (to be called "narrow gauge"), such as the Ffestiniog Railway. Thus it permitted a future multiplicity of narrow gauges in the UK. It also made no comments about future gauges in British colonies, which allowed various gauges to be adopted across the colonies.

Parts of the United States, mainly in the Northeast, adopted the same gauge, because some early trains were purchased from Britain. The American gauges converged, as the advantages of equipment interchange became increasingly apparent. Notably, all the 5 ft (1,524 mm) broad gauge track in the South was converted to "almost standard" gauge 4 ft 9 in (1,448 mm) over the course of two days beginning on 31 May 1886.[20] See Track gauge in the United States.

In continental Europe, France and Belgium adopted a 1,500 mm (4 ft 11+1⁄16 in) gauge (measured between the midpoints of each rail's profile) for their early railways.[21] The gauge between the interior edges of the rails (the measurement adopted from 1844) differed slightly between countries, and even between networks within a country (for example, 1,440 mm or 4 ft 8+11⁄16 in to 1,445 mm or 4 ft 8+7⁄8 in in France). The first tracks in Austria and in the Netherlands had other gauges (1,000 mm or 3 ft 3+3⁄8 in in Austria for the Donau Moldau line and 1,945 mm or 6 ft 4+9⁄16 in in the Netherlands for the Hollandsche IJzeren Spoorweg-Maatschappij), but for interoperability reasons (the first rail service between Paris and Berlin began in 1849, first Chaix timetable) Germany adopted standard gauges, as did most other European countries.

The modern method of measuring rail gauge was agreed in the first Berne rail convention of 1886.[22]

Early railways by gauge

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Non-standard gauge

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Almost standard gauge

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Standard gauge

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Small deviations from standard gauge

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Dual gauge

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Initially standard gauge

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Several lines were initially built as standard gauge but were later converted to another gauge for cost or for compatibility reasons.[citation needed]

• South Africa became

  1,067 mm

  (

  3 ft 6 in

  )
• Thailand became

  1,000 mm

  (

  3 ft 

  3

  +

  3

  ⁄

  8

   in
  )
• Indonesia became

  1,067 mm

  (

  3 ft 6 in

  )
• Ireland became

  1,600 mm

  (

  5 ft 3 in

  ) – Dublin and Kingstown Railway
• Australia became

  1,600 mm

  (

  5 ft 3 in

  ) – Victoria & South Australia – partly converted to

  1,435 mm

  (

  4 ft 

  8

  +

  1

  ⁄

  2

   in
  )
• India became

  1,676 mm

  (

  5 ft 6 in

  ) – initial freight lines
• some private Japanese railways

Modern almost standard gauge railways

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Railways

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Non-rail use

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Several states in the United States had laws requiring road vehicles to have a consistent gauge to allow them to follow ruts in the road. Those gauges were similar to railway standard gauge.[61]

See also

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Notes

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1. ^

   The gaps in the pedestrian crossings in Pompeii could give credence or otherwise to this statement, but no relevant studies appear to have been made.

2. ^[50] 298 km (185 mi) for NSCR extensions,[51] 92 km (57 mi) for the Northeast Commuter Line to [52][53] 581 to 639 km (361 to 397 mi) for the South Main Line rehabilitation, 71 km (44 mi) for the Subic–Clark Railway, 244 km (152 mi) for the [54] and 175 km (109 mi) for the Tarlac–San Fernando line.[55] Proposed MRT lines have a total length of 370 km (230 mi), discounting the Monorail [56] while LRT Line 6's total proposed track length is 169 km (105 mi).[57] All figures mentioned denote track length, not line or system length.

   For the Philippine National Railways, 2,278 km (1,415 mi) for the Mindanao Railway, 296 km (184 mi) for the North–South Commuter Railway (NSCR),298 km (185 mi) for NSCR extensions,92 km (57 mi) for the Northeast Commuter Line to Cabanatuan 581 to 639 km (361 to 397 mi) for the South Main Line rehabilitation, 71 km (44 mi) for the Subic–Clark Railway, 244 km (152 mi) for the San Jose Tuguegarao line,and 175 km (109 mi) for the Tarlac–San Fernando line.Proposed MRT lines have a total length of 370 km (230 mi), discounting the Monorail Line 4 LRT Line 1 extension is 26 km (16 mi),while LRT Line 6's total proposed track length is 169 km (105 mi).All figures mentioned denote track length, not line or system length.

References

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Bibliography

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Cross sectional shape of a railway rail

For the vertical alignment of a track, see Track geometry § Alignment

Rail from 1896 showing manufacturer's name and specification formed onto the web of rail during rolling. Cross-sections of flat-bottomed rail which can rest directly on the sleepers, and bullhead rails which sit in chairs (not shown). Early rails in US Section of the Translohr guidance rail (during the Clermont-Ferrand installation in 2006)

The rail profile is the cross sectional shape of a railway rail, perpendicular to its length.

Early rails were made of wood, cast iron or wrought iron. All modern rails are hot rolled steel with a cross section (profile) approximate to an I-beam, but asymmetric about a horizontal axis (however see grooved rail below). The head is profiled to resist wear and to give a good ride, and the foot profiled to suit the fixing system.

Unlike some other uses of iron and steel, railway rails are subject to very high stresses and are made of very high quality steel. It took many decades to improve the quality of the materials, including the change from iron to steel. Minor flaws in the steel that may pose no problems in other applications can lead to broken rails and dangerous derailments when used on railway tracks.

By and large, the heavier the rails and the rest of the track work, the heavier and faster the trains these tracks can carry.

Rails represent a substantial fraction of the cost of a railway line. Only a small number of rail sizes are made by steelworks at one time, so a railway must choose the nearest suitable size. Worn, heavy rail from a mainline is often reclaimed and downgraded for re-use on a branch line, siding or yard.

History

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Fishbelly edge rails laid on stone blocks on the Cromford and High Peak Railway Cross sections of early rails Stephenson-rail-patent half-lap jointed fishbelly rail patented in 1816

The earliest rails used on horse-drawn wagonways were wooden,[1]. In the 1760s strap-iron rails were introduced with thin strips of cast iron fixed onto the top of the wooden rails. This increased the durability of the rails. [2] Both wooden and strap-iron rails were relatively inexpensive, but could only carry a limited weight. The metal strips of strap-iron rails sometimes separated from the wooden base and speared into the floor of the carriages above, creating what was referred to as a "snake head". The long-term maintenance expense involved outweighed the initial savings in construction costs.[3][2]

Cast-iron rails with vertical flanges were introduced by Benjamin Outram of B. Outram & Co. which later became the Butterley Company in Ripley. The wagons that ran on these plateway rails had a flat profile. Outram's partner William Jessop preferred the use of "edge rails" where the wheels were flanged and the rail heads were flat - this configuration proved superior to plateways. Jessop's (fishbellied) first edge rails were cast by the Butterley Company.[4]

The earliest of these in general use were the so-called cast iron fishbelly rails from their shape. Rails made from cast iron were brittle and broke easily. They could only be made in short lengths which would soon become uneven. John Birkinshaw's 1820 patent,[5] as rolling techniques improved, introduced wrought iron in longer lengths, replaced cast iron and contributed significantly to the explosive growth of railroads in the period 1825–40. The cross-section varied widely from one line to another, but were of three basic types as shown in the diagram. The parallel cross-section which developed in later years was referred to as bullhead.

Meanwhile, in May 1831, the first flanged T rail (also called T-section) arrived in America from Britain and was laid into the Pennsylvania Railroad by Camden and Amboy Railroad. They were also used by Charles Vignoles in Britain.

The first steel rails were made in 1857 by Robert Forester Mushet, who laid them at Derby station in England.[6] Steel is a much stronger material, which steadily replaced iron for use on railway rail and allowed much longer lengths of rails to be rolled.

The American Railway Engineering Association (AREA) and the American Society for Testing Materials (ASTM) specified carbon, manganese, silicon and phosphorus content for steel rails. Tensile strength increases with carbon content, while ductility decreases. AREA and ASTM specified 0.55 to 0.77 percent carbon in 70-to-90-pound-per-yard (34.7 to 44.6 kg/m) rail, 0.67 to 0.80 percent in rail weights from 90 to 120 lb/yd (44.6 to 59.5 kg/m), and 0.69 to 0.82 percent for heavier rails. Manganese increases strength and resistance to abrasion. AREA and ASTM specified 0.6 to 0.9 percent manganese in 70 to 90 pound rail and 0.7 to 1 percent in heavier rails. Silicon is preferentially oxidised by oxygen and is added to reduce the formation of weakening metal oxides in the rail rolling and casting procedures.[7] AREA and ASTM specified 0.1 to 0.23 percent silicon. Phosphorus and sulfur are impurities causing brittle rail with reduced impact-resistance. AREA and ASTM specified maximum phosphorus concentration of 0.04 percent.[8]

The use of welded rather than jointed track began in around the 1940s and had become widespread by the 1960s.

Types

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Strap rail

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Strap rail and spike

The earliest rails were simply lengths of timber. To resist wear a thin iron strap was laid on top of the timber rail. This saved money as wood was cheaper than metal. The system had the flaw that every so often the passage of the wheels on the train would cause the strap to break away from the timber. The problem was first reported by Richard Trevithick in 1802. The use of strap rails in the United States (for instance on the Albany and Schenectady Railroad c. 1837) led to passengers being threatened by "snake-heads" when the straps curled up and penetrated the carriages.[2]

T rail

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T-rail was a development of strap rail which had a 'T' cross-section formed by widening the top of the strap into a head. This form of rail was generally short-lived, being phased out in America by 1855.[9]

Plate rail

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Plate rail was an early type of rail and had an 'L' cross-section in which the flange kept an unflanged wheel on the track. The flanged rail has seen a minor revival in the 1950s, as guide bars, with the Paris Métro (Rubber-tyred metro or French Métro sur pneus) and more recently as the Guided bus. In the Cambridgeshire Guided Busway the rail is a 350 mm (14 in) thick concrete beam with a 180 mm (7.1 in) lip to form the flange. The buses run on normal road wheels with side-mounted guidewheels to run against the flanges. Buses are steered normally when off the busway, analogous to the 18th-century wagons which could be manoeuvered around pitheads before joining the track for the longer haul.

Bridge rail

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"Bridge rail" redirects here. For the traffic-barrier or guard-rail on a bridge, see Bridge barrier

Bridge rail is a rail with an inverted-U profile. Its simple shape is easy to manufacture, and it was widely used before more sophisticated profiles became cheap enough to make in bulk. It was notably used on the Great Western Railway's 7 ft 1⁄4 in (2,140 mm) gauge baulk road, designed by Isambard Kingdom Brunel.

Barlow rail

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Barlow rail was invented by William Henry Barlow in 1849. It was designed to be laid straight onto the ballast, but the lack of sleepers (ties) meant that it was difficult to keep it in gauge.

Flat bottomed rail

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Cross section of new flat bottomed rail

Flat bottomed rail is the dominant rail profile in worldwide use.

Flanged T rail

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Flanged T rail (also called T-section) is the name for flat bottomed rail used in North America. Iron-strapped wooden rails were used on all American railways until 1831. Col. Robert L. Stevens, the President of the Camden and Amboy Railroad, conceived the idea that an all-iron rail would be better suited for building a railroad. There were no steel mills in America capable of rolling long lengths, so he sailed to the United Kingdom which was the only place where his flanged T rail (also called T-section) could be rolled. Railways in the UK had been using rolled rail of other cross-sections which the ironmasters had produced.

In May 1831, the first 500 rails, each 15 feet (4.6 m) long and weighing 36 pounds per yard (17.9 kg/m), reached Philadelphia and were placed in the track, marking the first use of the flanged T rail. Afterwards, the flanged T rail became employed by all railroads in the United States.

Col. Stevens also invented the hooked spike for attaching the rail to the crosstie (or sleeper). In 1860, the screw spike was introduced in France where it was widely used.[10] Screw spikes are the most common form of spike in use worldwide in the 21st century.[citation needed]

Flat-bottom or Vignoles rail

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Vignoles Rail as used for the London and Croydon Railway in 1839 Vignoles rail as used for the Birmingham and Gloucester Railway in 1840

Vignoles rail is the popular name for flat-bottomed rail, recognising engineer Charles Vignoles who introduced it to Britain. Charles Vignoles observed that wear was occurring with wrought iron rails and cast iron chairs on stone blocks, the most common system at that time. In 1836 he recommended flat-bottomed rail to the London and Croydon Railway for which he was consulting engineer. His original rail had a smaller cross-section than the Stevens rail, with a wider base than modern rail, fastened with screws through the base. Other lines which adopted it were the Hull and Selby, the Newcastle and North Shields, and the Manchester, Bolton and Bury Canal Navigation and Railway Company.[11]

When it became possible to preserve wooden sleepers with mercuric chloride (a process called Kyanising) and creosote, they gave a much quieter ride than stone blocks and it was possible to fasten the rails directly using clips or rail spikes. Their use, and Vignoles's name, spread worldwide.

The joint where the ends of two rails are connected to each other is the weakest part of a rail line. The earliest iron rails were joined by a simple fishplate or bar of metal bolted through the web of the rail. Stronger methods of joining two rails together have been developed. When sufficient metal is put into the rail joint, the joint is almost as strong as the rest of the rail length. The noise generated by trains passing over the rail joints, described as "the clickity clack of the railroad track", can be eliminated by welding the rail sections together. Continuously welded rail has a uniform top profile even at the joints.

Double-headed rail

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In late 1830s Britain, railway lines had a vast range of different patterns. One of the earliest lines to use double-headed rail was the London and Birmingham Railway, which had offered a prize for the best design. This rail was supported by chairs and the head and foot of the rail had the same profile. The supposed advantage was that, when the head became worn, the rail could be turned over and re-used. In practice, this form of recycling was not very successful as the chair caused dents in the lower surface, and double-headed rail evolved into bullhead rail in which the head was more substantial than the foot.

Bullhead rail

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Bullhead rail was the standard for the British railway system from the mid-19th until the mid-20th century. For example, in 1954 bullhead rail was used for 449 miles (723 km) of new track and flat-bottom for 923 miles (1,485 km).[12] One of the first British Standards, BS 9, was for bullhead rail - it was originally published in 1905, and revised in 1924. Rails manufactured to the 1905 standard were referred to as "O.B.S." (Original), and those manufactured to the 1924 standard as "R.B.S." (Revised).[13]

Bullhead rail is similar to double-headed rail except that the profile of the head of the rail is not the same as that of the foot. Bullhead rail evolved from double-headed rail but, because it did not have a symmetrical profile, it was never possible to flip it over and use the foot as the head. Therefore, because the rail no longer had the originally-perceived benefit of reusability, it was a very expensive method of laying track. Heavy cast iron chairs were needed to support the rail, which was secured in the chairs by wooden (later steel) wedges or "keys" which required regular attention.

Bullhead rail has now been almost completely replaced by flat-bottom rail on British railways, although it survives on the national rail system in some sidings or branch lines. It can also be found on heritage railways, due both to the desire to maintain an historic appearance, and the salvage and reuse of old track components from the main lines. The London Underground continued to use bullhead rail after it had been phased out elsewhere in Britain, but in the last few years has there been a concerted effort to convert its track to flat-bottom rail.[14] However, the process of replacing track in tunnels is a slow process due to the impossibility of using heavy plant and machinery.

Grooved rail

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Grooved rail, used when track is laid in places traversed by other vehicles or pedestrians

Where a rail is laid in a road surface (pavement) or within grassed surfaces, there has to be accommodation for the flange. This is provided by a slot called the flangeway. The rail is then known as grooved rail, groove rail, or girder rail. The flangeway has the railhead on one side and the guard on the other. The guard carries no weight, but may act as a checkrail.

Grooved rail was invented in 1852 by Alphonse Loubat, a French inventor who developed improvements in tram and rail equipment, and helped develop tram lines in New York City and Paris.[15] The invention of grooved rail enabled tramways to be laid without causing a nuisance to other road users, except unsuspecting cyclists, who could get their wheels caught in the groove. The grooves may become filled with gravel and dirt (particularly if infrequently used or after a period of idleness) and need clearing from time to time, this being done by a "scrubber" vehicle (either a specialised tram, or a maintenance road-rail vehicle). Failure to clear the grooves can lead to a bumpy ride for the passengers, damage to either wheel or rail and possibly derailing.

Girder guard rail

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The traditional form of grooved rail is the girder guard section illustrated to the left. This rail is a modified form of flanged rail and requires a special mounting for weight transfer and gauge stabilisation. If the weight is carried by the roadway subsurface, steel ties are needed at regular intervals to maintain the gauge. Installing these means that the whole surface needs to be excavated and reinstated.

Block rail

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Block rail is a lower profile form of girder guard rail with the web eliminated. In profile it is more like a solid form of bridge rail, with a flangeway and guard added. Simply removing the web and combining the head section directly with the foot section would result in a weak rail, so additional thickness is required in the combined section.[16]

A modern block rail with a further reduction in mass is the LR55 rail[17] which is polyurethane grouted into a prefabricated concrete beam. It can be set in trench grooves cut into an existing asphalt road bed for Light Rail (trams).[18]

Rail weights and sizes

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Two commonly used rail profiles: a heavily worn 50-kg/m profile and a new 60-kg/m profile

The weight of a rail per length is an important factor in determining rail strength and hence axleloads and speeds.

Weights are measured in pounds per yard (imperial units are used in Canada, the United Kingdom and United States) or kilograms per metre (metric units are used in Australia and mainland Europe). 1 kg/m = 2.0159 lb/yd.

Commonly, in rail terminology pound is a metonym for the expression pounds per yard and hence a 132–pound rail means a rail of 132 pounds per yard.

Europe

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Rails are made in a large number of different sizes. Some common European rail sizes include:

• 40 kg/m (81 lb/yd)
• 50 kg/m (101 lb/yd)
• 54 kg/m (109 lb/yd)

• 56 kg/m (113 lb/yd)
• 60 kg/m (121 lb/yd)

In the countries of the former USSR, 65 kg/m (131 lb/yd) rails and 75 kg/m (151 lb/yd) rails (not thermally hardened) are common. Thermally hardened 75 kg/m (151 lb/yd) rails also have been used on heavy-duty railroads like Baikal–Amur Mainline, but have proven themselves deficient in operation and were mainly rejected in favor of 65 kg/m (131 lb/yd) rails.[citation needed]

North America

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Weight mark "155 PS" on a jointed segment of 155 lb/yd (76.9 kg/m) "Pennsylvania Special" rail, the heaviest grade of rail ever mass-produced Cross-section drawing showing measurements in Imperial units for 100 lb/yd (49.6 kg/m) rail used in the United States, c.

 1890s

New York Central System Dudley 127 lb/yd (63.0 kg/m) rail cross section

The American Society of Civil Engineers (or ASCE) specified rail profiles in 1893 for 5 lb/yd (2.5 kg/m) increments from 40 to 100 lb/yd (19.8 to 49.6 kg/m). Height of rail equaled width of foot for each ASCE tee-rail weight; and the profiles specified fixed proportion of weight in head, web and foot of 42%, 21% and 37%, respectively. ASCE 90 lb/yd (44.6 kg/m) profile was adequate; but heavier weights were less satisfactory. In 1909, the American Railway Association (or ARA) specified standard profiles for 10 lb/yd (4.96 kg/m) increments from 60 to 100 lb/yd (29.8 to 49.6 kg/m). The American Railway Engineering Association (or AREA) specified standard profiles for 100 lb/yd (49.6 kg/m), 110 lb/yd (54.6 kg/m) and 120 lb/yd (59.5 kg/m) rails in 1919, for 130 lb/yd (64.5 kg/m) and 140 lb/yd (69.4 kg/m) rails in 1920, and for 150 lb/yd (74.4 kg/m) rails in 1924. The trend was to increase rail height/foot-width ratio and strengthen the web. Disadvantages of the narrower foot were overcome through use of tie plates. AREA recommendations reduced the relative weight of rail head down to 36%, while alternative profiles reduced head weight to 33% in heavier weight rails. Attention was also focused on improved fillet radii to reduce stress concentration at the web junction with the head. AREA recommended the ARA 90 lb/yd (44.6 kg/m) profile.[19] Old ASCE rails of lighter weight remained in use, and satisfied the limited demand for light rail for a few decades. AREA merged into the American Railway Engineering and Maintenance-of-Way Association in 1997.

By the mid-20th century, most rail production was medium heavy (112 to 119 lb/yd or 55.6 to 59.0 kg/m) and heavy (127 to 140 lb/yd or 63.0 to 69.4 kg/m). Sizes under 100 lb/yd (49.6 kg/m) rail are usually for lighter duty freight, low use trackage, or light rail. Track using 100 to 120 lb/yd (49.6 to 59.5 kg/m) rail is for lower speed freight branch lines or rapid transit; for example, most of the New York City Subway system track is constructed with 100 lb/yd (49.6 kg/m) rail.[citation needed] Main line track is usually built with 130 lb/yd (64.5 kg/m) rail or heavier. Some common North American rail sizes include:[20]

Crane rails

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Some common North American crane rail sizes include:

• 12 lb/yd (5.95 kg/m)
• 20 lb/yd (9.9 kg/m)
• 25 lb/yd (12.4 kg/m)
• 30 lb/yd (14.9 kg/m)
• 40 lb/yd (19.8 kg/m)

• 60 lb/yd (29.8 kg/m)
• 80 lb/yd (39.7 kg/m)
• 85 lb/yd (42.2 kg/m)
• 104 lb/yd (51.6 kg/m)

• 105 lb/yd (52.1 kg/m)
• 135 lb/yd (67 kg/m)
• 171 lb/yd (84.8 kg/m)
• 175 lb/yd (86.8 kg/m)

Australia

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Some common Australian rail sizes include:

• 30 kg/m (60 lb/yd)
• 36 kg/m (73 lb/yd)
• 40 kg/m (81 lb/yd)
• 47 kg/m (95 lb/yd)

• 50 kg/m (101 lb/yd)
• 53 kg/m (107 lb/yd)
• 60 kg/m (121 lb/yd)
• 68 kg/m (137 lb/yd)

• 50 kg/m and 60 kg/m are the current standard, although some other sizes are still manufactured.[21]
• Some larger U.S. sizes are used on northwest Western Australian iron ore railways.

Rail lengths

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The 130-metre (430 ft) rail, which would be the world's longest rail line in a single piece, was rolled at URM, Bhilai Steel Plant (SAIL) on 29 November 2016.[22] In order of date then length:

Welding of rails into longer lengths was first introduced around 1893. Welding can be done in a central depot, or in the field.

Conical or cylindrical wheels

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It has long been recognised that conical wheels and rails that are sloped by the same amount follow curves better than cylindrical wheels and vertical rails. A few railways such as Queensland Railways for a long time had cylindrical wheels until much heavier traffic required a change.[25] Cylindrical wheel treads have to "skid" on track curves so increase both drag and rail and wheel wear. On very straight track a cylindrical wheel tread rolls more freely and does not "hunt". The gauge is narrowed slightly and the flange fillets keep the flanges from rubbing the rails. United States practice is a 1 in 20 cone when new. As the tread wears it approaches an unevenly cylindrical tread, at which time the wheel is trued on a wheel lathe or replaced.[citation needed]

Manufacturers

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Rails are made from high quality steel and not in huge quantities compared with other forms of steel, and so the number of manufacturers in any one country tends to be limited.

Defunct manufacturers

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Standards

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• EN 13674-1 - Railway applications - Track - Rail - Part 1: Vignole railway rails 46 kg/m and above EN 13674-1
• EN 13674-4 - Railway applications - Track - Rail - Part 4: Vignole railway rails from 27 kg/m to, but excluding 46 kg/m EN 13674-4

See also

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References

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