Forged Fishplates for Light and Heavy Rails

Forged fishplates for light and heavy rails are steel connectors manufactured through a forging process. They are installed at the ends of rails and connected to each other using high-strength bolts to form a continuous track. Fishplates for light and heavy rails differ in size, strength, and design to adapt to different rail types (e.g., below 50kg/m for light rails and 50-75kg/m for heavy rails) and operating conditions. The forging process ensures that the fishplates have high strength, toughness, and fatigue resistance, meeting the high load and vibration requirements of railway operation.

According to the rail type, structure, and application, forged fishplates can be divided into the following types:

（1）Light Rail Fishplates

• Features：
  • Adapted to light rail types, such as 43kg/m, below 50kg/m rails (commonly used in urban light rail or mining railways).
  • Smaller size, length about 400-600mm, thickness 10-15mm, weight 5-10kg/pair.
  • The number of bolt holes is usually 4, the hole diameter is 22-26mm, and M20-M24 bolts are used.
• Applicable Scenarios：Urban light rail, tramway, industrial railways, mining railways.
• Advantages：Light weight, easy installation, and low cost.
• Disadvantages：Low strength, not suitable for high-speed or heavy-load railways.

（2）Heavy Rail Fishplates

• Features：
  • Adapted to heavy rail types, such as 50kg/m, 60kg/m, 75kg/m (commonly used in high-speed rail and freight railways).
  • Larger size, length about 600-820mm, thickness 15-20mm, weight 10-20kg/pair.
  • The number of bolt holes is 4 or 6, the hole diameter is 26-30mm, and M24-M30 high-strength bolts (grade 10.9) are used.
• Applicable Scenarios：High-speed railways (high-speed rail), heavy-load freight railways, main line railways.
• Advantages：High strength, fatigue resistance, suitable for high axle loads (>20 tons) and high speeds (>200km/h).
• Disadvantages：Heavy weight, high processing and installation costs.

（3）Insulated Fishplates

• Features：
  • Used for track circuit insulation to prevent current short circuits, using high-strength composite materials or surface-insulated steel.
  • The size and hole positions are the same as ordinary fishplates, but the surface is coated with an insulating layer (such as epoxy coating) or non-conductive shims are used.
• Applicable Scenarios：Signal control areas, track circuit areas.
• Advantages：Combines connection and insulation functions to ensure signal system stability.
• Disadvantages：High cost, the insulation layer needs to be checked regularly.

（4）Special Fishplates

• Features：
  • Customized design, such as widened fishplates (to enhance lateral stability) or transition fishplates (to connect different rail types, such as 50kg/m to 60kg/m).
  • Can be equipped with buffer pads or shock absorption devices to reduce vibration and noise.
• Applicable Scenarios：Turnout areas, bridge tracks, or special working conditions.
• Advantages：Adapts to complex environments, performance optimization.
• Disadvantages：Complex processing, high cost.

Materials and Structural Features

• Materials：
  • Carbon Steel：Q235 (yield strength 235 MPa) is used for light rail fishplates, and Q345 (yield strength 345 MPa) is used for heavy rail fishplates.
  • Alloy Steel：Such as 40Cr, 45# steel, tensile strength 600-800 MPa, suitable for high-strength heavy rail fishplates.
  • Stainless Steel：304/316, corrosion-resistant, suitable for coastal or high-humidity environments.
  • Density：Approximately 7850 kg/m³ (carbon steel/alloy steel), 7800 kg/m³ (stainless steel).
  • Surface Treatment：Hot-dip galvanizing (thickness 60-80μm) or spraying (80-120μm) for corrosion protection, and some are phosphated to improve wear resistance.
• Structural Design：
  • Shape：Fishplate shape, symmetrical up and down, narrowed in the middle, widened at both ends, and fits the rail web.
  • Size：Length 400-820mm, width 120-150mm, thickness 10-20mm, adapted to rail types (such as 50kg/m, 60kg/m).
  • Bolt Holes：4-6, hole diameter 22-30mm, hole spacing 100-150mm, tolerance ±0.2mm.
  • Strength：Tensile strength >600 MPa, shear strength >300 MPa, meeting UIC 864 or TB/T 2345 standards.
  • Clearance：A gap of 1-2mm is left between the fishplate and the rail to allow for thermal expansion and contraction (temperature change ±40°C).