What holds two rails together?
Jan 28, 2026
A rail fish plate is a structural coupling device that aligns rail ends and maintains straightness and curvature continuity, preventing step differences that would otherwise generate impact forces at wheel passage. It ensures smooth mechanical transition between two rail bars. GNEE RAIL manufactures and supplies fish plates matched to international rail sections and project-specific requirements, integrating them with rail supply under EN, UIC, DIN, JIS, AS, BS, and AREMA systems.
What holds two rails together?
Two railway rails are primarily held together at their ends by a fish plate (also known as a joint bar or splice bar). These metal plates are bolted onto both sides of the rail web, bridging the gap between two rails to ensure alignment, stability, and smooth, continuous passage for trains.
Key details regarding rail connections include:
- Components: Fish plates are secured using high-strength rail bolts, nuts, and spring washers.
- Function: They maintain the structural integrity of the track, reducing the impact of wheels on the jointed sections.
- Alternatives: For higher speeds and modern, smoother, or quieter tracks, rails may be connected via thermite welding to form Continuous Welded Rail (CWR), which eliminates the need for joints.
- Model Railroading: In smaller scales, a small, often metal, piece called a fishplate slips over the rail ends to maintain alignment and electrical conductivity.
How to install a rail joint?
Installing a railway joint (fishplate) involves aligning two rail ends, cleaning the area, positioning the joint bars, and securing them with lubricated bolts in a specific sequence to handle thermal expansion. Ensure a gap of less than 5 mm between rails, use suitable fishplates, and tighten bolts in a 4- or 6-hole pattern.
- Preparation: Clean the rail ends, removing debris, rust, and old oil. If necessary, use a grinder to ensure the rail ends are perpendicular to the track.
- Lubrication: Apply oil or lubricant to the contacting surfaces of the fishplate, rail web, and fish bolts.
- Positioning: Place the fishplates (rail joints) on both sides of the rail web. Ensure the joint gasket is correctly inserted.
- Bolt Installation: Insert bolts, ensuring they are staggered (some facing inward, some outward).
- Tightening Sequence: For a 4-hole joint, tighten the middle two bolts first, then the outer two. If it is a 6-hole joint, start from the center and move outward.
- Final Checks: Ensure the rail gauge is within ±3 mm and the joint is level, with no more than 2mm vertical deviation.
Specification of Railway Joint
| Joint Type | Key Specification / Description |
|---|---|
| Standard Rail Joint (Fish Plate) | - Profile: Matches the rail section (e.g., UIC 60, 136RE). - Length: Typically 600mm or 800mm per side. - Holes: 4 or 6 bolt holes per bar. |
| Insulated Rail Joint (IRJ) | - Material: Steel core with composite insulating end-posts/plates, or full epoxy composite. - Electrical Resistance: >10⁸ Ω. |
| Compromise Rail Joint | - Design: Connects two different rail profiles (e.g., UIC 54 to UIC 60). - Profile: Each side is machined to match its respective rail section. |
| Joggled Rail Joint | - Feature: Has a depressed (joggled) section to allow continuous rail head surface for smoother wheel passage. |
| Bridge Rail Joint | - Design: Often reinforced (thicker web/longer length) for high-stress locations like bridge approaches. |
| Glued Insulated Joint | - Construction: Steel bars bonded to composite insulation using high-strength adhesive for improved durability. |
| Welded Rail Joint (for CWR) | - Type: Flash-butt or thermite weld. - Specification: Weld must meet mechanical properties equal to or greater than the parent rail. |
| Expansion Joint (for BRE) | - Feature: Allows controlled thermal expansion in long rails on bridges or in extreme temperature zones. |
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.
