A rail fish plate is a bolted joint bar that maintains rail alignment and stiffness continuity, preventing rail end separation and misalignment caused by thermal movement and heavy axle loads. It ensures smooth wheel transition across rail joints. GNEE RAIL supplies fish plates for GB 8–60 kg/m, UIC50–UIC60, DIN536 A55–A120, QU70–QU120, JIS 15KG–CR100, AS1085 31–89 kg, BS11, and AREMA/ASCE standards.
What is the diameter of a rail hole normally provided for a fish plate joint?
The diameter of a rail hole (or bolt hole) for a fish plate joint is typically around 32mm (approx. 1.25 inches). These holes, which allow for thermal expansion/contraction of rails, are often slightly larger than the fish bolts themselves, with standard hole diameters ranging from 26.5mm to 32mm depending on the rail section.
Key Details on Rail Hole Diameters:
- Common Diameter: The most common hole size for standard fish plates is 32mm, designed to accommodate bolts for joining two rails.
- Bolt Size Relation: The bolt holes are drilled to be slightly larger than the fish bolts, allowing for expansion and contraction.
- Typical Bolt Diameters: Standard fish bolt diameters are often 25mm (BG), 22mm (MG), and 18mm (NG).
- Hole Configuration: Fish plates typically have 4 or 6 bolt holes, with a diameter of roughly 32mm.
What is the material of the rail joint bar?
Rail joint bars (also known as fishplates, splice bars, or rail joints) are typically constructed from high-strength, durable materials like hot-rolled steel, carbon steel, or specialized alloy steel (such as Q235 or Q255). For electrical insulation in signaling systems, they are made from reinforced plastics, epoxy, or fiberglass.
Key Materials and Types:
- Standard Rail Joint Bars: Fabricated from steel,, offering high durability and strength for heavy traffic.
- Insulated Rail Joint Bars: Produced from thermosetting materials, such as alkali-free glass fiber reinforced epoxy resin, which is non-conductive, rustproof, and resistant to corrosion.
- Components & Coating: Some insulated bars utilize polyurethane, while metallic bars can be oiled, painted, or galvanized for protection.
| Material Type | Typical Grade / Designation | Chemical Composition (wt%) | Notes / Equivalent Standards |
|---|---|---|---|
| Carbon Structural Steel | Q235 (GB/T 700) | C: ≤0.22 Si: ≤0.35 Mn: 0.30-0.65 P: ≤0.045 S: ≤0.045 |
Common mild steel for general joint bars. Similar to ASTM A36, S235JR. |
| Carbon Structural Steel | Q255 (GB/T 700) | C: 0.18-0.28 Si: ≤0.35 Mn: 0.40-0.70 P: ≤0.045 S: ≤0.045 |
Slightly higher strength than Q235. |
| Medium Carbon Steel | 50Mn / 50BA (GOST 10779) | C: 0.47-0.55 Si: 0.17-0.37 Mn: 0.80-1.20 P: ≤0.040 S: ≤0.045 |
Classic high-strength fish plate steel. Widely used for mainline joints. |
| Medium Carbon Steel | 55# (GB/T 699) | C: 0.52-0.60 Si: 0.17-0.37 Mn: 0.50-0.80 P: ≤0.035 S: ≤0.035 |
Standard medium carbon steel for demanding applications. Similar to AISI 1055. |
Types of Rail Fish Plate
Rail fish plates (joint bars) connect rail ends to ensure structural continuity, commonly categorized by application into Standard (4-6 holes), Insulated (for signaling), Compromise (for different rail sizes), and Joggled (for temporary repairs) types. They are made from high-strength steel, cast iron, or composite materials, and are used on light, heavy, or crane rails.
| 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.