What are fish plates made of

Feb 04, 2026 Leave a message

A rail fish plate is a mechanical coupling bar that ensures alignment and load cooperation between adjoining rail lengths by binding their webs with high-strength bolts. GNEE RAIL supplies fish plates matched to GB light and heavy rails, UIC standard rails, DIN536 and QU crane rail applications, JIS rail profiles, AS1085 sections, BS11 rails, and AREMA/ASCE standards, supported by dimensional inspection services.

 

rail joint

 

Standard Type Length/Diameter Weight /Material  
AREMA 2007 115RE 4 hole-24" 17.04Kg 45# chemical
115RE 6 hole-36" 25.56Kg composition(%):
132-136RE 4 hole-24" 17.75Kg C: 0.42-0.50
132-136RE 6 hole-36" 26.63Kg Mn: 0.50-0.80
UIC864 UIC60 4 hole-630/Φ26 18.07Kg Si: 0.17-0.37
UIC60 4 hole-600/Φ28 17.47Kg Cr: ≤0.25
UIC60 4 hole-630/Φ25 18.1Kg P: ≤0.035
UIC54 4 hole 14.34Kg S: ≤0.035
UIC54 6 hole-800 19.94Kg  
BS 47-1 BS75R 4 hole 6.56Kg  
BS60A 4 hole 5.61Kg  
BS80A 4 hole 6.5Kg  
BS90A 685.8/Φ26 13.23Kg 50# chemical
BS90A 792.9/Φ26.2 15.34Kg composition(%):
BS100A 4 hole   C: 0.62-0.70
  90/91LB 4 hole 18.08Kg Mn: 0.50-0.80
90/91LB 6 hole 19.9Kg Si: 0.17-0.37
AS 50kg 4 hole 14.3Kg Cr: ≤0.25
50kg 6 hole 19.5Kg P: ≤0.035
  S49 4 hole 9.71Kg S: ≤0.035

 

What are fish plates made of?

 

Fish plates (or splice bars) used in railway tracks are predominantly made of high-strength, durable materials designed to withstand heavy loads and wear, typically hot-rolled or forged carbon steel. Common steel types include 45#, 50Mn, 42CrMo, Q235, and Q355, often enhanced with Manganese or Copper.

 

rail joint

 

Material Type Typical Grade / Designation Chemical Composition (wt%) Notes / Equivalent Standards
Carbon Structural Steel Q235 (GB/T 700) C: ≤0.22 Common mild steel for general joint bars. Similar to ASTM A36, S235JR.
Si: ≤0.35
Mn: 0.30-0.65
P: ≤0.045
S: ≤0.045
Carbon Structural Steel Q255 (GB/T 700) C: 0.18-0.28 Slightly higher strength than Q235.
Si: ≤0.35
Mn: 0.40-0.70
P: ≤0.045
S: ≤0.045
Medium Carbon Steel 50Mn / 50BA (GOST 10779) C: 0.47-0.55 Classic high-strength fish plate steel. Widely used for mainline joints.
Si: 0.17-0.37
Mn: 0.80-1.20
P: ≤0.040
S: ≤0.045
Medium Carbon Steel 55# (GB/T 699) C: 0.52-0.60 Standard medium carbon steel for demanding applications. Similar to AISI 1055.
Si: 0.17-0.37
Mn: 0.50-0.80
P: ≤0.035
S: ≤0.035
Alloy Steel 42CrMo (GB/T 3077) C: 0.38-0.45 High-strength, high-toughness alloy for severe service. Similar to AISI 4140/4142.
Si: 0.17-0.37
Mn: 0.50-0.80
Cr: 0.90-1.20
Mo: 0.15-0.25
P: ≤0.035
S: ≤0.035
Spheroidal Graphite Cast Iron QT450-10 (GB/T 1348) C: 3.60-3.90 Used in some traditional/joint kits for its castability and damping properties. Similar to EN-GJS-450-10.
Si: 2.00-3.00
Mn: ≤0.50
P: ≤0.07
S: ≤0.015
Mg: 0.03-0.06 (Nodulizer)
Insulating Composite Material Epoxy Fiberglass / FRP Base: Epoxy Resin No metallic elements. Provides electrical insulation (Resistivity >10¹² Ω·cm), corrosion resistance.
Reinforcement: E-Glass Fiber (>60%)
Additives: Hardener, fillers (e.g., SiO₂)

 

Which material is the most durable for rail fish plates?

 

High-strength alloy steel is the most durable material for rail fish plates, offering superior fatigue resistance, high tensile strength, and long service life for heavy-haul railways. These steel plates outperform ordinary carbon steel by reducing bolt loosening and deformation, making them ideal for high-traffic or high-speed lines.

 

Top Choice: High-strength alloy steel (heat-treated) provides the best durability and longevity.

 

rail fish plate

 

Alternatives:

 

  • Stainless Steel: Best for highly corrosive environments (coastal/industrial).

 

  • Composite/Fiberglass: Offers excellent corrosion resistance and electrical insulation, ideal for specialized applications.

 

  • Ductile Iron: Used in some low-traffic areas, but generally less durable than steel.

 

For maximum durability and reliability in heavy-duty applications, specialized heat-treated alloy steel is considered the industry standard.

 

What is the service life of a rail joint bar?

 

The service life of a rail joint bar typically ranges from 5 to 10 years for standard, well-maintained bolted joints, but varies significantly based on traffic and type. Insulated rail joints often last 8–15 years, while specialized or high-impact compromise joints can fail within 2 weeks to 2 months.

 

Key factors affecting the service life of rail joint bars include:

 

  • Joint Type: Standard joint bars generally last longer than insulated joints, which are considered the weakest link and have a shorter lifespan due to higher dynamic impacts.

 

rail joint

 

Classification Category Type of Rail Joint Core Definition / Key Characteristics
By Position on Track Square Joint Joints on parallel rails are aligned opposite each other. Common on straight tracks; simple but causes more impact.
Staggered Joint Joints on one rail are opposite the mid-point of the adjacent rail. Primarily used on curves to reduce forces and improve ride quality.
By Position of Sleepers Supported Joint Rail ends rest directly on a single "joint sleeper". Minimizes deflection but creates a rigid, high-maintenance point.
Suspended Joint Rail ends are located between two sleepers. The most common type; offers flexibility but requires more frequent maintenance.
Bridge Joint Similar to suspended, but uses a metal bridge plate to connect rails on either side of the joint. Not widely used.
By Performance & Application Ordinary (Bolted) Joint Standard connection using fishplates and bolts. Cost-effective, allows for thermal expansion.
Compromise Joint Connects two rails of different sizes/profiles. Uses specially shaped fishplates to ensure a smooth transition.
Conductive Joint Ensures electrical continuity between rail sections for traction current and signaling, using conductive materials.
Insulated Joint (IRJ) Electrically isolates rail sections for signaling systems. Uses insulating materials between rails and plates.
Welded Joint Rail ends are fused together (e.g., thermite welding). Creates Continuous Welded Rail (CWR) for a smoother, stronger track.
Frozen Joint A defective condition where tight or corroded fishplates prevent thermal expansion/contraction, leading to high stress.
Expansion Joint (REJ) Allows controlled longitudinal rail movement (e.g., on bridges) to prevent buckling or breakage due to temperature changes.

 

  • Maintenance: Proper maintenance, such as tightening fish bolts, can extend the life of the joint, while lack of maintenance leads to premature failure.

 

  • Operating Conditions: High traffic volume and harsh environments increase wear, reducing the lifespan of the joints.

 

joint bar

 

  • Material and Design: High-strength steel, like 42CrMo, with proper heat treatment, can improve wear and fatigue resistance.

 

Insulated rail joints often require replacement at a rate 10 times faster than the rail itself, often lasting only 12–18 months in some applications. Compromise joints, which connect rails of different sizes, are particularly vulnerable and require frequent inspections.

 

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.

 

Click here to obtain the detailed product catalog of GNEE RAIL.