Rail Fish Plates Explained: Types, Standards, Dimensions and Selection Guide

Rail fish plate, also known as joint bars, are essential components used to connect two rail ends and maintain track continuity. They are widely used in mainline railways, metro systems, industrial rail tracks, crane rails, mining railways, and other rail infrastructure projects.

Although modern railways increasingly use continuously welded rail (CWR), rail joints remain necessary in turnouts, bridges, temporary tracks, industrial sidings, crane rail systems, and maintenance applications. Selecting the correct fish plate is therefore critical for track safety, load transfer, and long-term reliability.

This guide explains rail fish plate types, international standards, material specifications, dimensions, manufacturing methods, and practical selection criteria for railway projects.

Rail Fish Plate in Railway Fastening Systems

A rail fish plate is only one component within a complete railway fastening assembly. In jointed track systems, fish plates work together with several other track components to maintain rail alignment and transfer wheel loads safely through the track structure.

Typical components used together include:

• Rail Fish Plates
• Fish Bolts and Nuts
• Rail Clips
• Rail Pads
• Sleepers

Each component serves a specific purpose. Rail clips provide clamping force, rail pads reduce vibration and impact, fish bolts secure the joint, and sleepers distribute loads into the ballast or supporting structure. Proper interaction between these components is essential for long-term track stability.

What Is a Rail Fish Plate?

A rail fish plate is a steel bar with pre-drilled bolt holes, installed in pairs on both sides of a rail joint. It is secured with fish bolts and nuts, clamping two rail ends together to form a continuous running surface.

The primary functions of a rail fish plate include:

• Load transfer across the rail gap
• Maintaining vertical and horizontal alignment
• Accommodating thermal expansion in jointed track
• Supporting signaling requirements in insulated joints

A poorly specified or poorly manufactured fish plate can lead to rail-end batter, bolt loosening, joint pumping, fatigue cracking, and ultimately increased maintenance costs.

Common Rail Fish Plate Products We Manufacture

Fonyo manufactures a wide range of standard and custom rail fish plates for railway, metro, industrial, and crane rail applications.

UIC Standard Fish Plates

Common profiles include:

• UIC60 Fish Plate
• UIC54 Fish Plate
• UIC50 Fish Plate
• S49 Fish Plate

These products are widely used in railway projects throughout Europe, Asia, Africa, and the Middle East.

AREMA Joint Bars

Common North American profiles include:

• 136RE Joint Bar
• 132RE Joint Bar
• 115RE Joint Bar
• 100RE Joint Bar

AREMA joint bars are commonly used on freight railways, industrial spurs, and passenger rail networks.

Crane Rail Fish Plates

For industrial and crane rail systems, we manufacture:

• A45 Fish Plates
• A55 Fish Plates
• A65 Fish Plates
• A75 Fish Plates
• QU70 Fish Plates
• QU80 Fish Plates
• QU100 Fish Plates

Custom Fish Plates

We also provide:

• Insulated Joint Bars
• Compromise Joint Bars
• Joggled Fish Plates
• Drawing-Based Custom Designs

Custom manufacturing is available according to customer drawings, rail profiles, and project specifications.

Types of Rail Fish Plates by International Standard

Rail fish plates are manufactured to different dimensional profiles depending on the rail section they connect. The three dominant standard systems are UIC (European), AREMA (North American), and DIN (industrial rail). Each system defines its own set of rail profiles and corresponding joint bar dimensions.

UIC Fish Plate (European Standard)

The International Union of Railways (UIC) standard covers the most widely used rail profiles in Europe, Asia, Africa and the Middle East. UIC fish plates are designed to match specific UIC rail sections and comply with UIC 864 performance requirements.

Common UIC fish plate profiles include:

UIC fish plates are typically available in 4-hole and 6-hole configurations, with 6-hole being the standard for mainline applications. They are manufactured from hot-rolled steel with minimum tensile strength of 550-700 MPa depending on the grade specified.

AREMA Joint Bars (North American Standard)

The American Railway Engineering and Maintenance-of-Way Association (AREMA) standard governs rail infrastructure in North America. AREMA joint bars are covered under Chapter 4 of the AREMA Manual and are designed for specific AREMA rail sections.

Common AREMA joint bar profiles include:

AREMA joint bars are typically 24-inch or 36-inch length, with 4 or 6 bolt holes. The steel grade requirement per AREMA is typically Grade 55 (minimum yield strength 55 ksi / 380 MPa) or higher, with Charpy impact testing required for certain applications.

Key Differences: UIC vs AREMA Fish Plate

DIN Fish Plate (Industrial & Crane Rail)

For industrial railways, crane runways, and specialized track systems, DIN standards define rail sections and corresponding fish plates. Common applications include overhead crane rails (A series), light crane rails (KS series), and mine railways.

DIN fish plates are generally lighter than mainline counterparts and may use different bolt patterns. They are specified by the DIN rail profile number — for example, a DIN A 65 fish plate matches an A 65 crane rail. These components are often custom-manufactured due to the wide variety of crane rail profiles in service.

Rail Fish Plate Dimensions and Specifications

Fish plate dimensions vary according to rail profile, rail weight, operating conditions, and applicable railway standards.

Typical specifications include:

Dimension details should always be verified against the applicable railway standard or project drawings.

For non-standard applications, custom machining and OEM production are available.

Types of Rail Fish Plate by Design & Application

Beyond the standard profile-based classification, fish plates are also categorized by their design features and intended use case.

Standard Joint Bars (4-Hole / 6-Hole)

The most common type, designed for general-purpose rail joints on plain line track. Four-hole bars are used on lighter rail sections and secondary lines; six-hole bars provide greater clamping force and are standard for mainline and heavy-haul applications. The additional bolt holes distribute the joint load more evenly and improve resistance to rail-end batter.

Insulated Joint Bars (IJs)

Insulated joint bars incorporate a layer of insulating material — typically epoxy-fiberglass composite — between the bar and the rail web. They electrically isolate two track sections for signaling and train detection purposes. The insulation must maintain integrity under cyclic loading, temperature extremes and moisture exposure. Insulated joints are critical components in modern signaling systems and require strict quality control during manufacture.

Compromise Joint Bars (Transition Bars)

When two different rail sections need to be joined — for example, transitioning from UIC 60 to UIC 54 — a compromise joint bar is used. It has an asymmetric profile: one half matches the heavier rail section and the other half matches the lighter section. Compromise bars are precision-machined to ensure the running surface and gauge face align correctly across the transition.

Joggled (Cranked) Fish Plates

Joggled fish plates feature an offset or crank in their profile, designed to fit around obstructions at the rail joint. They are commonly used at switch and crossing (S&C) assemblies, in tight-clearance locations, and where standard fish plates would interfere with adjacent track components. These are typically custom-fabricated items.

Material Specifications for Rail Fish Plate

The material quality of a fish plate determines its fatigue life, wear resistance and safety margin. Rail fish plates operate under high-cycle fatigue conditions — every wheel pass applies a load cycle at the joint — so material selection is critical.

Common Steel Grades

Coating & Corrosion Protection

Fish plates may be supplied with the following surface treatments depending on environmental conditions:

• Black / oiled finish — standard for general applications
• Hot-dip galvanizing — for corrosive environments (coastal, tropical)
• Sherardizing — zinc diffusion coating for uniform thread protection
• Painting / epoxy coating — specified for certain metro and tunnel applications

Corrosion protection selection should consider the full service environment: humidity, salt exposure, chemical exposure (industrial sidings), and maintenance accessibility.

Material selection directly affects fatigue resistance, wear performance, and service life. Similar material control principles are widely applied to other railway components such as railway wheels, rail clips, bogie castings, and fastening system parts.

How Rail Fish Plates Are Manufactured

The manufacturing process plays a significant role in determining mechanical performance and dimensional accuracy.

A typical production process includes:

1. Raw Material Inspection
2. Hot Rolling or Forging
3. Heat Treatment
4. CNC Machining
5. Precision Drilling
6. Surface Treatment
7. Final Inspection
8. Packaging and Shipment

At Fonyo Heavy Industries, every production stage is controlled through documented inspection procedures and full material traceability.

Quality Control Measures

Inspection typically includes:

• Chemical composition analysis
• Tensile testing
• Hardness testing
• Dimensional inspection
• Coating thickness measurement
• Visual surface inspection

Third-party inspections such as SGS, BV, and TÜV can also be arranged according to project requirements.

How to Choose a Reliable Rail Fish Plate Manufacturer

Selecting the correct fish plate is important, but selecting the right manufacturer is equally critical.

Key evaluation criteria include:

Manufacturing Capability

• Forging and rolling capacity
• CNC machining capability
• Custom production capability

Quality Assurance

• Material certificates
• Inspection reports
• Traceability system

Standards Compliance

• UIC
• EN
• AREMA
• DIN

Project Experience

Manufacturers with experience in railway, metro, industrial rail, and international export projects are generally better equipped to meet project-specific requirements.

How to Choose the Right Fish Plate: A 5-Step Process

Step 1: Identify Your Rail Profile

The fish plate must match the rail section exactly. Check your rail marking: UIC rails are stamped on the web with the profile designation (e.g. “UIC 60”). AREMA rails carry similar markings (e.g. “136 RE”). If the markings are worn, measure the rail height and head width or consult engineering drawings.

Step 2: Determine the Applicable Standard

Your project specification will dictate whether UIC, AREMA or DIN standards apply. This is typically driven by geography — European-funded projects specify UIC/EN, North American projects specify AREMA — but may also be determined by the railway operator’s internal standards or the engineering consultant’s design basis.

Step 3: Assess Operating Conditions

Key factors to evaluate:

• Axle load — heavier loads may require higher-grade steel or longer fish plates
• Annual tonnage — high-traffic lines demand better fatigue resistance
• Speed — high-speed lines have tighter alignment tolerances
• Curvature — curved track imposes additional lateral forces on joints
• Environment — coastal, tropical or chemically aggressive environments require appropriate coatings

Step 4: Select Bolt Hole Configuration

Match the fish plate bolt hole pattern to your fish bolt specification. The most common configurations are:

• 4-hole — secondary lines, metro, light rail
• 6-hole — mainline, heavy-haul, high-speed

Bolt hole diameter must correspond to the fish bolt diameter. Common sizes: M22, M24, M27 for UIC systems; 7/8″, 1″ for AREMA systems.

Step 5: Verify Manufacturing Quality Requirements

Confirm that the manufacturer provides:

• Material test certificates (chemical composition, tensile strength)
• Dimensional inspection reports
• Coating thickness measurement records (if coated)
• Third-party inspection availability (SGS, BV, TUV, etc.)

Frequently Asked Questions About Rail Fish Plates

What is the difference between a fish plate and a joint bar?

They are the same component. “Fish plate” is the term used in British and international English; “joint bar” is the North American (AREMA) term. Both refer to the steel bars used to connect two rail ends at a joint.

Can I use a UIC fish plate on an AREMA rail?

No. UIC and AREMA rail sections have different profiles, and their fish plates are not interchangeable. Using the wrong standard will result in poor contact at the rail web and fishing angles, leading to accelerated wear and potential failure.

How many fish plates do I need per rail joint?

Two — one on each side of the rail web. A standard rail joint uses a pair of fish plates (one left, one right) secured by fish bolts.

What bolt torque is required for fish plate installation?

Torque values depend on bolt size and grade. For M24 Grade 8.8 fish bolts, typical torque is 250-350 Nm. For 1″ AREMA bolts, 400-600 ft-lbs is common. Always follow the project specification or manufacturer’s recommendation.

Do fish plates come in matched pairs?

Yes. Fish plates are supplied and installed in matched pairs — the left and right bars are mirror images. Ordering is typically by the pair or by the set (pair + bolts).

How do I identify the correct fish plate for my rail?

Check the rail marking on the web, or measure the rail profile. Our engineering team can assist with profile identification from rail dimensions or photographs. CAD drawings are available for verification.

What is the difference between a 4-hole and 6-hole fish plate?

Six-hole fish plates provide more clamping force and better load distribution. They are commonly used on mainline and heavy-haul railways. Four-hole fish plates are typically used on lighter rail sections and secondary tracks.

Can rail fish plates be manufactured according to drawings?

Yes. Custom fish plates can be produced according to customer drawings, rail profile measurements, or project specifications. Engineering review and drawing verification are typically provided before production.

Need Custom Rail Fish Plates or Joint Bars?

Luoyang Fonyo Heavy Industries manufactures UIC, AREMA, DIN, crane rail, and custom rail fish plates for railway infrastructure projects worldwide.

Our engineering team can assist with:

• Rail profile identification
• Fish plate selection
• CAD drawing verification
• Material specification review
• OEM manufacturing

In addition to fish plates, we also supply fish bolts, rail clips, rail pads, railway sleepers, and other railway track components.

Contact us today for technical support, engineering consultation, and quotations.