Rail fastening system
Encyclopedia
This article is about devices used to fasten rail to railroad ties (sleepers), for devices used to join lengths of rail see Fishplate
Fishplate
In rail terminology, a fishplate, splice bar or joint bar is a metal bar that is bolted to the ends of two rails to join them together in a track. The name is derived from fish, a wooden bar with a curved profile used to strengthen a ship's mast...

"Rail spike" redirects here. For the Transformer, see Railspike
Railspike
Railspike is the name of several fictional characters in the various Transformers universes.-Transformers: Robots in Disguise:Railspike is an Autobot train. Railspike is the grizzled leader of the Team Bullet Train. He is courageous and polite, and his intelligence makes him akin to any battlefield...

.

A rail fastening system is a means of fixing rails
Rail profile
The rail profile is the cross sectional shape of a railway rail, perpendicular to the length of the rail.In all but very early cast iron rails, a rail is hot rolled steel of a specific cross sectional profile designed for use as the fundamental component of railway track.Unlike some other uses of...

 to railroad ties (United States) or sleepers (international). The terms rail anchors, tie plates, chairs and track fasteners are used to refer to parts or all of a rail fastening system. Various types of fastening have been used over the years.

History and overview

The earliest wooden rails were fixed to wooden sleepers by pegs through holes in the rail, or by nails. By the 17th century cast iron rails had come into use, and also had holes in the rail itself to allow them to be fixed to a support. 18th century developments such as the flanged rail and fish bellied rail also had holes in the rail itself; when stone block sleepers were used the nails were driven into a wooden block which had been inserted into a recess in the block. The first chair for a rail is thought to have been introduced in 1797 which attached to the rail on the vertical web via bolts.

By the 1820s the first shaped rolled rails had begun to be produced initially of a T shape which required a chair to hold them; the rails were held in position by iron wedges (which sometimes caused the rail to break when forced in) and later by wooden wedges, which became the standard. In the 1830s Robert L. Stevens invented the flanged 'tee' rail (actually a distorted I beam), which had a flat bottom and required no chair, a similar design was the contemporary bridge rail (an inverted 'U' shaped with bottom flange and used on longitudinal sleepers); these rails were initially nailed directly to the sleeper.

In North American practice the flanged T rail became the standard, later being used with tie-plates. Elsewhere T rails were replaced by bull head rails of a rounded 'I' or 'figure-8' appearance which still required a supporting chair. Eventually the flanged T rail became commonplace on all the worlds railways, though differences in the fixing system still exist.

Rail spikes

A rail spike (also known as a cut spike or crampon) is a large nail
Nail (engineering)
In woodworking and construction, a nail is a pin-shaped, sharp object of hard metal or alloy used as a fastener. Formerly wrought iron, today's nails are typically made of steel, often dipped or coated to prevent corrosion in harsh conditions or improve adhesion...

 with an offset head that is used to secure rails and base plates to railroad tie
Railroad tie
A railroad tie/railway tie , or railway sleeper is a rectangular item used to support the rails in railroad tracks...

s in the track. Robert Livingston Stevens
Robert Livingston Stevens
Colonel Robert Livingston Stevens was the son of Colonel John Stevens. In 1807, the father and son built the Phœnix, a steamship which became the first steamship to navigate the ocean successfully when she traveled from New York City to the Delaware River in 1809...

 is credited with the invention of the railroad spike, being first used in at least 1832. The railroad spike was an invention which resulted from the state of industrialisation in the United States in the early 19th century: English mainline railways of that period used heavy and expensive cast iron chairs to secure T shaped rails; instead, Stevens added a supporting base to the T rail which could be fixed with a simple spike. The spike is still (as of 1982) the most common rail fastening in North America. Common sizes are from 9 to 10/16 inch square and ~5.5 to 6 inch long.

A rail spike is roughly chisel shaped and with a flat edged point; the spike is driven with the edge against the grain, which gives greater resistance to loosening. The main function is to keep the rail in gauge. When attaching tie plates the attachment is made as strong as possible, whereas when attaching a rail to tie or tie plate the spike is not normally required to provide a strong vertical force, allowing the rail some freedom of movement.

Originally spikes were driven into wooden sleepers by hammering them with a heavy hammer by hand. This manual work has been replaced by machines, commonly called "spike drivers" (A machine that removes spikes is called a "spike puller"). Splitting of the wood can be limited by pre-boring spike holes or adding steel bands around the wood.

For use in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 three basic standards are described in the ASTM A65 standard, for different carbon steel contents.

The rail spike has entered American popular consciousness; the driving of the "Golden Spike
Golden spike
The "Golden Spike" is the ceremonial final spike driven by Leland Stanford to join the rails of the First Transcontinental Railroad across the United States connecting the Central Pacific and Union Pacific railroads on May 10, 1869, at Promontory Summit, Utah Territory...

" was a key point in North American development of the western seaboard. Also characters such John Henry (folklore)
John Henry (folklore)
John Henry is an American folk hero and tall tale. Henry worked as a "steel-driver"—a man tasked with hammering and chiseling rock in the construction of tunnels for railroad tracks. In the legend, John Henry's prowess as a steel-driver was measured in a race against a steam powered hammer,...

 have been celebrated in song and verse, as have railroad workers in general.

A dog spike is functionally equivalent to a cut spike and is also square in horizontal section and of similar dimensions but has a pointed penetrating head, and the rail (or "plate holding") head has two lugs on either side (which aid spike removal) giving the impression of a dog's head.

Screw spikes

A screw spike, rail screw (or lag bolt) is a large (~6" length, slightly under 1" diameter) metal screw used to fix a tie plate or fasten rail. Screw spikes are fixed into a hole bored in the sleeper. The screw spike has a higher cost to manufacture than the rail spike but has the advantage of greater fixing power; approximately twice that of a rail spike, and can be used in combination with spring washers.

The screw spike was first introduced in 1860 in France (French tire-fond), and became common in continental Europe.

Fang bolts

Fang bolts have also been used for fixing rails or chairs to sleepers; the fang bolt is a bolt inserted through a hole in the sleeper with a fanged nut that bites into the lower surface of the sleeper. For fastening flat-bottomed rails an upper-lipped washer can be used to grip the edge of the rail. They are more resistant to loosening by vibrations and movement of the rail. They are thought more effective than spikes and screws and so are used in positions such as switch (point) tieplates, and on sharp curves.

Spring spikes

Spring spikes, (or elastic rail spikes) are used with flat-bottomed rail, baseplates and wooden sleepers; the spring spike holds the rail down and prevents tipping, and also secures the baseplate to the sleeper. The Macbeth spike (trade name) is a two-pronged U-shaped staple
Staple (fastener)
A staple is a type of two-pronged fastener, usually metal, used for joining or binding materials together. Large staples might be used with a hammer or staple gun for masonry, roofing, corrugated boxes and other heavy-duty uses...

-like spike bent so that it appears M-shaped when viewed from the side. Inverted J-shaped single pointed spikes have also been used.

Fixing equipment

The spike maul
Spike maul
A Spike Maul is a type of hand tool used to drive railroad spikes in railroad track work.Spike mauls are akin to the sledge hammer, typically weighing from with a long handle.They have an elongated double faced hardened steel head...

 also known as a spiking hammer, a type of sledgehammer with a long thinnish head was originally used to drive spikes.

Manual hole drilling and spike or screw insertion and removal have been replaced by semi-automated or automated machines, both pneumatic and hydraulic. Machines that remove spikes are called spike pullers.

Chairs

The earliest railway chairs, made of cast iron, were introduced around 1800 used to fix and support cast-iron rails at the ends; they were also used to join the adjacent rails.

In the 1830s T-shaped (or single-flanged T parallel rail) and I-shaped rails (double-flanged T parallel or bullhead rail) rolled rails were introduced; both required cast-iron chairs to support them. Originally, iron keys were used to wedge the rail into the vertical parallel jaws of the chair; these were superseded by entirely wooden keys. The wooden keys were formed from oak, steam softened and then compressed with hydraulic presses and stored in a drying house; when inserted into the chair, exposure to the wet atmosphere would cause the key to expand, firmly holding the rail. The wedge may be on the inside or outside of the rail (usually the outside).

Chairs have been fixed to the sleeper using wooden spikes (trenails), screws, fang-bolts or spikes.

In most of the world, flat-bottomed rail and baseplates became the standard, however in Britain, bullhead rail-and-chairs remained in use until the middle of the twentieth century. They are now largely obsolete but can still be found on London Underground
London Underground
The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...

 and sidings
Rail siding
A siding, in rail terminology, is a low-speed track section distinct from a running line or through route such as a main line or branch line or spur. It may connect to through track or to other sidings at either end...

.

Tie plates

A tie plate, baseplate or sole plate is a steel plate used on rail tracks between flanged T rail and the crossties
Railroad tie
A railroad tie/railway tie , or railway sleeper is a rectangular item used to support the rails in railroad tracks...

. The tie plate increases bearing area and holds the rail to correct gauge
Rail gauge
Track gauge or rail gauge is the distance between the inner sides of the heads of the two load bearing rails that make up a single railway line. Sixty percent of the world's railways use a standard gauge of . Wider gauges are called broad gauge; smaller gauges, narrow gauge. Break-of-gauge refers...

. They are fastened to wooden ties by means of spikes or bolts through holes in the plate.

The part of the plate under the rail base is tapered, setting the cant
Cant (road/rail)
The cant of a railway track or a road is the difference in elevation between the two edges...

 of the rail, an inward rotation from the vertical. The usual slope is one in forty ( 1.4 degrees ). The top surface of the plate has one or two shoulders that fit against the edges of the base of the rail. The double-shoulder type is currently used. Older single-shoulder types were adaptable for various rail widths, with the single shoulder positioned on the outside (field side) of the rails. Most plates are slightly wider on the field side, without which the plates tend to cut more into the outsides of the tie, reducing cant angle.

Many railways use large wood screws, also called lag screws, to fasten the tie plates (or baseplates) to the railroad ties.

Tie plates came into use around the year 1900, before which time flanged T rail was spiked directly to the ties.

Clips

A variety of different types of heavy-duty clips are used to fasten the rails to the underlying baseplate, one common one being the Pandrol
Pandrol
Pandrol is a British company, which manufactures clips used on rail tracks.- Overview :The was patented in 1957 by a Norwegian railways engineer, Per Pande Rolfsen. Nowadays it is common worldwide. Pandrol has manufacturing plants in 12 countries and 82 markets. Over 240 railway systems in 91...

 fastener (Pandrol clip), named after its maker, which is shaped like a stubby paperclip. Another one is the Vossloh Tension Clamp.

The newer Pandrol fastclip is applied at right angles to the rail. Because the clip is captive, it has to be installed at the time of manufacture of the concrete sleeper.

See also

  • Permanent way (history) and permanent way (current), descriptions of the entire track system.

External links

  • Images:
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