Fastening Fish Plates

Function Type

Model

Key Features

Application Scenario

Compatible Rail (kg/m)

Installation Requirement

Advantage

Disadvantage

Standard Fish Plate

FP-S60

Basic joint connection, flat structure

General passenger/freight railways (non-high-speed)

43–60

Bolt torque: 300–350N·m; Joint gap ≤1mm

Low cost, easy installation

Low vibration resistance, short service life in heavy-haul

High-Speed Fish Plate

FP-HS350

Curved contact surface, integrated buffer layer

High-speed railways (≥300km/h)

60 (CRH special rail)

Bolt torque: 400–450N·m; Coaxiality of bolt holes ≤0.2mm

Excellent vibration absorption, low joint stiffness variation

High manufacturing cost, strict installation precision

Heavy-Haul Fish Plate

FP-HD75

Thickened structure (thickness ≥25mm), high-strength material

Heavy-haul freight railways (axle load ≥30t)

60–75

Bolt torque: 450–500N·m; Preload force ≥120kN

High load-bearing capacity, wear resistance

Heavy weight, difficult manual installation

Insulated Fish Plate

FP-INS50

Integrated insulating layer (resin material), non-conductive bolts

Electrified railways (signal section division)

43–50

Insulation resistance ≥10⁸Ω; No metal contact between rail and plate

Prevent signal interference, good insulation performance

Low impact toughness, easy insulation layer damage

Adjustable Fish Plate

FP-ADJ60

Telescopic structure, adjustable joint gap (0–3mm)

Railway in cold regions (large temperature difference)

50–60

Adjust gap according to temperature (≥-30℃: 1–2mm; ≤-30℃: 2–3mm)

Adapt to temperature-induced rail expansion/contraction

Complex structure, high maintenance frequency

Failure Mode

Occurrence Position

Main Cause

Detection Method

Short-Term Solution

Bolt Hole Cracking

Around bolt holes (especially stress concentration area)

1. Stress concentration (hole edge radius <2mm); 2. Over-torque during installation

1. Visual inspection (crack length ≥0.5mm); 2. Penetrant testing

1. Drill stop hole at crack end; 2. Reduce installation torque by 10%

Contact Surface Wear

Rail-fish plate contact surface

1. Relative sliding between rail and plate (vibration); 2. Poor lubrication

1. Thickness measurement (wear depth ≥1mm); 2. Surface roughness test (Ra ≥6.3μm)

1. Polish worn surface; 2. Apply molybdenum disulfide lubricant

Plate Body Bending

Middle of fish plate

1. Insufficient plate thickness (≤15mm for 60kg/m rail); 2. Overload operation (axle load > design value)

1. Straightedge test (bending deformation ≥2mm); 2. Level measurement

1. Replace bent fish plate; 2. Limit axle load to design value

Insulation Layer Degradation

Insulating layer (insulated fish plate)

1. Moisture intrusion (humid environment); 2. Mechanical impact (rail displacement)

1. Insulation resistance test (≤10⁶Ω); 2. Visual inspection (layer peeling)

1. Dry insulation layer with hot air; 2. Repair peeling area with epoxy resin

Joint Loosening

Rail-fish plate joint

1. Bolt relaxation (vibration); 2. Wear of bolt thread

1. Torque check (torque loss ≥20%); 2. Gap measurement (joint gap ≥3mm)

1. Retighten bolts to standard torque; 2. Replace worn bolts