What are the 4 main types of joints?
Jan 28, 2026
A rail fish plate is a bolted joint element that grips the rail web and foot zone to stabilize rail ends against vertical bending, lateral shifting, and rotational movement. It converts two separate rail bars into a functionally continuous beam over the joint area. GNEE RAIL provides joint bar systems for standard railway rails, mining rails, and crane rails, offering compatible bolts, washers, rail drilling services, and on-site technical support.
What are the 4 main types of joints?
The 4 main types of rail joints, widely used to connect steel rails and maintain track continuity, are common (or standard) rail joints, compromise joints, insulated joints, and welded joints. These joints ensure proper alignment, safety, and operational efficiency, with specialized options used for differing rail sizes or electrical signaling.
- Common/Standard Rail Joint: Joins two rails of the same type and standard dimension together.
- Compromise Rail Joint: Connects two rails of different, non-matching sizes or sections.
- Insulated Rail Joint: Used in electric track circuits, these joints provide electrical isolation between track sections, often using high-strength composite materials.
- Welded Joint/Rail: Instead of bolt-supported, these rails are welded to provide a continuous, seamless, and smoother ride, reducing maintenance.
| 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. |
What is the working principle of a railfish plate?
A rail fish plate (or joint bar) functions by bracing the web and fishing surfaces (underside of the head and top of the base) of two rail ends, clamping them together with bolts to ensure vertical/horizontal alignment, structural continuity, and load transfer. It reduces wheel impact on joints and maintains gauge.
Key Working Principles:
- Structural Load Transfer: Fish plates act as beams that bridge the gap between rail ends, distributing heavy wheel loads across the joint to prevent deflection and reduce stress.
- Alignment Maintenance: By clamping tightly to the rail sides, they keep the top table (running surface) and gauge face (inside edge) of adjoining rails in precise alignment, preventing steps or gaps.
- Friction & Tension: The tapered design allows them to wedge tightly between the rail head and flange. Proper torque on the fish bolts ensures the plates hold the rail ends securely, minimizing relative movement.
- Expansion/Contraction: They allow for small, controlled longitudinal movements caused by thermal expansion, preventing rail buckling or breaks.
What is the material of the rail joint?
Rail joints are primarily made from high-strength steel (medium or high-carbon steel), including materials like Q235, Q255, forged steel, or spheroidal graphite cast iron for traditional, conductive connections. Insulated rail joints use non-conductive materials such as specialized reinforced plastics, epoxy-impregnated glass fiber, or thermosetting composites.
Key Materials Breakdown:
- Common/Traditional Joints: Typically constructed from steel bars (hot-rolled, forged, or cast) to ensure structural strength and electrical conductivity.
- Insulated/Joint Kits: Utilize composite materials, such as fiberglass and epoxy resin, which provide high insulation, corrosion resistance, and durability.
- Components: Bolts and nuts used to secure the joints are also typically made of high-strength steel.
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.
