- Fishplate
:"This article relates to the connection bar used in railways. For the type of Greek pottery, see
Fish plate ."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 thescarf joint s then in use. It was first deployed on theEastern Counties Railway in 1844. He patented his invention in England, Ireland and Scotland but, supposedly by some underhand means, the patent shortly afterwards passed toJames Samuel , the engineer of the ECR.Electrical connection
When railway lines are equipped with
track circuit s, or where the line is electrified for electric traction, the electrical connection provided by fishplates is too poor and unreliable and has to be supplemented by bonding wire which is spot welded to the two rails either side of the joint.Alternatives
Even though fishplates strengthen the weak points represented by rail joints, improvements can still be made. For example, the joints can be welded together using the
thermite process.References
* Ellis, C. Hamilton (1958). "Twenty Locomotive Men", Ian Allan Ltd, London.
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