Fish plate

Fish-plate Karlsruhe BM F266

Fish plate

A fish plate, also known as a joint bar, splice bar, or rail joint, is a metal bar that is bolted to the ends of two rail tracks to join them together in a track. The name "fish plate" is derived from "fish," a nautical term for a piece of wood or iron used to strengthen a mast or spar.

Design and Function

Fish plates are designed to maintain the alignment of the rail tracks and ensure a smooth transition between the rail ends. They are typically made from steel and are bolted to the rail ends using track bolts. The fish plate has a flat surface that fits against the web of the rail, and it is usually designed with a slight curvature to match the profile of the rail.

Installation

The installation of fish plates involves aligning the rail ends, placing the fish plate over the joint, and securing it with bolts. Proper installation is crucial to ensure the stability and safety of the railway track. The bolts must be tightened to the correct torque to prevent loosening due to vibrations and thermal expansion.

Types of Fish Plates

There are several types of fish plates used in railway construction, including:

• **Standard Fish Plates**: Used for general rail joints.
• **Insulated Fish Plates**: Used in sections of track where electrical insulation is required, such as in signaling systems.
• **Compromise Fish Plates**: Used to join rails of different sizes or profiles.

Maintenance

Regular maintenance of fish plates is essential to ensure the safety and longevity of the railway track. This includes periodic inspection for wear and tear, checking for loose bolts, and replacing damaged fish plates. Proper maintenance helps prevent rail misalignment and potential derailments.

Historical Context

The use of fish plates dates back to the early days of railway construction. They were first introduced in the 19th century as a means to join rail sections more efficiently than the previously used methods, such as lap joints and butt joints. The introduction of fish plates significantly improved the stability and reliability of railway tracks.

See Also

• Rail fastening system
• Rail profile
• Railroad tie
• Track gauge
• Rail transport