Rail fishplate used for connect steel rail

Edit:Zongxiang Heavy Industry--Ethan Date:2025-04-23 10:56:27

A rail fishplate, also known as a joint bar or splice bar, is a crucial component in railway track construction. Its primary function is to connect two sections of steel rail together in a secure and aligned manner. Without fishplates, the rails would not stay properly aligned, leading to unsafe conditions and potential derailments. This relatively small component plays a significant role in the overall safety and performance of railway systems.

Design and Material

A rail fishplate is a flat metal bar, typically made from forged or rolled steel, designed to be placed on either side of the web (the vertical center part) of a rail. It is usually about 60 to 70 cm long and has bolt holes that align with holes in the rail ends. The fishplate is fastened to the rails using bolts and nuts, creating a solid and aligned joint.

The design includes a machined inner surface that precisely fits the rail profile, ensuring tight contact with the rail’s head and web. Some fishplates also have a slightly tapered or chamfered edge to help absorb shock and minimize movement under the load of passing trains.

Function and Importance

Fishplates serve multiple functions in railway tracks:

Mechanical Connection: They hold the ends of two rails together, maintaining continuity and alignment. This is vital for the smooth passage of train wheels from one rail to the next.

Load Distribution: They help distribute the vertical and lateral loads from train wheels, reducing wear on the rail ends.

Electrical Continuity: In some electrified rail systems, specially designed fishplates also ensure electrical continuity between rail sections, which is essential for track circuit signaling systems.

Ease of Maintenance: Fishplates make it easier to replace rail sections without disturbing the entire track, as they allow for easy disassembly and reassembly.

Types of Fishplates

There are several types of fishplates based on application:

Standard Fishplates: Used for general track connections with matching rail profiles.

Insulated Fishplates: Made of non-conductive materials or include insulation layers, used where electrical isolation between rail sections is needed.

Compromise Fishplates: Used to join rails of different sizes or profiles.

Glued Insulated Joints (GIJs): These are a more advanced version used in high-speed and heavy-load applications.

Installation and Maintenance

Proper installation is critical. The rail ends must be cut precisely and aligned properly. The fishplate is then placed in position, and bolts are tightened to specific torque requirements. Over time, bolts can loosen due to vibration and thermal expansion, so regular inspection and maintenance are essential.

Fishplates are also subject to wear and corrosion, especially in harsh environments. Modern railway systems increasingly use continuous welded rail (CWR), which reduces the number of joints and fishplates. However, fishplates are still extensively used in many regions and remain essential for temporary repairs, sidings, and older rail lines.