A fishplate joins two lengths of track. A fishplate, splice bar or joint bar is a metal or composites connecting plate used to bolt the ends of two rails into a continuous track. The name is derived from ''fish'', a wooden reinforcement of a "built-up" ship's mast that helped round out its desired profile. The top and bottom faces taper inwards along their short dimensions to create an even alignment between the two rails when the fish plate is wedged into place by tightening its bolts during installation. In

rail transport modelling Railway modelling (UK, Australia, New Zealand, and Ireland) or model railroading (US and Canada) is a hobby in which rail transport systems are Model building, modelled at a reduced Scale (ratio), scale. The scale models include locomotives ...

, a fishplate is often a small

copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...

nickel silver Nickel silver, maillechort, German silver, argentan, new silver, nickel brass, albata, or alpacca is a cupronickel (copper with nickel) alloy with the addition of zinc. The usual formulation is 60% copper, 20% nickel and 20% zinc. Nickel silver ...

plate that slips onto both rails to provide the functions of maintaining alignment and electrical continuity.

History

The device was invented by William Bridges Adams in May 1842, because of his dissatisfaction with the scarf joints and other systems of joining rails then in use. He noted that to form the scarf joint the rail was halved in thickness at its ends, where the stress was greatest. It was first deployed on the

Eastern Counties Railway The Eastern Counties Railway (ECR) was an English railway company incorporated in 1836 intended to link London with Ipswich via Colchester, and then extend to Norwich and Yarmouth. Construction began in 1837 on the first at the London end. Co ...

in 1844, but only as a wedge between the adjoining rails. Adams and Robert Richardson patented the invention in 1847, but in 1849 James Samuel, the engineer of the ECR, developed fishplates that could be bolted to the rails.

In rail switches

The moving blades of a

railroad switch A railroad switch (American English, AE), turnout, or (set of) points (Commonwealth English, CE) is a mechanical installation enabling railway trains to be guided from one Rail tracks, track to another, such as at a Junction (rail), ...

can be connected to the closure rails by looser-than-normal fishplates. This is called a heeled switch. Alternatively, the blade and closure rail can be a one-piece heel-less switch, with a flexible thinned section to create the moving heel.

Electrical bonding

When railway lines are equipped with

track circuit A track circuit is an electrical device used to prove the absence of a train on a block of rail tracks to control railway signals. An alternative to track circuits are axle counters. Principles and operation The basic principle behind the t ...

s, or where the line is electrified for electric traction, the electrical connection provided by fishplates is poor and unreliable and has to be supplemented by bonding wire spanning the joined rails fixed by spot welding or other means.

Welded joints

An improvement over fishplate rail connectors is directly bonding rails together using thermite or flash butt welding. In 1967, the Hither Green rail crash occurred on the Southern Region of

British Railways British Railways (BR), which from 1965 traded as British Rail, was a state-owned company that operated most rail transport in Great Britain from 1948 to 1997. Originally a trading brand of the Railway Executive of the British Transport Commis ...

when a rail fractured at its fishplate joint. The crash accelerated welded rail connections, with strict procedures on concrete and wooden sleepers.

References

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External links