How to fix a gap in a joint?

A rail fish plate is a joint reinforcement device that protects rail ends from excessive stress concentration by redistributing loads across bolted connections, extending rail service life. GNEE RAIL offers fish plates matched to GB light and heavy rails, UIC50/54/60, DIN536 crane rails, QU crane rails, JIS rails, AS1085 profiles, BS11 standards, and AREMA/ASCE rails.

What is the purpose of a fish plate in railway?

A fish plate (or joint bar) in a railway connects two rail ends together, ensuring structural continuity, alignment, and stability. By securely bolting to the sides of the rails, they maintain proper gauge, support vertical loads to prevent deflection, and allow for expansion/contraction, thus ensuring train safety and stability.

Key purposes of fish plates in railways include:

• Connecting Rails: They act as splice bars to join adjacent rail sections, creating a continuous track.

• Maintaining Alignment: They keep the rail ends perfectly aligned both horizontally and vertically, ensuring a smooth ride and preventing derailments.

• Load Distribution: They transfer the heavy vertical impact of train wheels from one rail to the next, reducing stress at the joint.

• Allowing Movement: Fish plates are designed to allow slight longitudinal movement, accommodating the thermal expansion and contraction of rails.

• Safety and Stability: By providing structural integrity to the rail joints, they prevent the rails from drifting apart.

How to fix a gap in a joint?

Fixing a gap in a rail fish plate involves tightening existing bolts to specified torques, replacing worn components, or, for persistent gaps (exceeding 0.5mm), installing manganese steel shims (0.3mm-0.5mm) to fill the space. Proper maintenance requires, if the joint has pulled apart, regulating adjacent rails, or temporarily, using two bolts with reduced speed, and for dipped joints, jacking up the rail.

Methods to Fix Fish Plate Gaps

• Tightening and Inspection: Use a torque wrench to tighten bolts in the correct sequence to eliminate looseness. If the gap between the rail head side and fishplate exceeds 0.5mm, replace it.

• Installing Shims: Insert 65Mn steel shims (0.3mm or 0.5mm) between the fishplate and the rail web to close the gap.

• Replacing Fishplates: If the fishplate is severely worn or damaged, replace it with a new one, ensuring it matches the rail profile.

• Joint Regulation: If the joint has pulled apart due to contraction, you may need to use rail tensors or expanders to close the gap, ensuring proper expansion gaps are maintained based on temperature.

• Lubrication: Clean the rail ends and fishplates, then apply a suitable lubricant to the fishing surfaces to ensure the rail can move freely, preventing sudden, large gaps.

Founded in 2008, GNEE RAIL is a leading global manufacturer and supplier of railway components, specializing in high-quality rail fish plates (joint bars/splice bars) with strong production capacity and global service capabilities.

Our rail fish plate portfolio is comprehensive and compliant with international standards including UIC, AREMA, BS, DIN, and GB, covering light rail (8kg-30kg), heavy rail (38kg-75kg), and crane rail (QU70-QU120) systems. We offer diverse types such as insulated joint bars, bulged fish plates, and compromise rail joints,with precise specifications (4-hole/6-hole, 24-inch/36-inch), ensuring excellent mechanical performance.We uphold strict quality control supported by ISO 9001:2015 certification, an in-house inspection center, and third-party audits by SGS and BV. Our one-stop service includes customization, production, packaging, and after-sales support, tailored to clients' project needs.

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