Fishplate Rail Joint Connection and Model Compatibility Technology
What are the core model classifications of fishplates and applicable rail specifications?
Fishplates are classified by national standard/foreign standard/rail weight, national standard fishplates are divided into 43/50/60/75kg/m models, foreign standard into UIC60/BS80A/AREMA136RE models, the models correspond to rail specifications precisely. 43kg/m fishplate is suitable for the same specification national standard rails, with 4 bolt holes, basic joint connection meeting light-load needs. 50/60kg/m fishplates are the main models for ordinary railway/high-speed railway connecting lines, with 6 bolt holes, higher connection strength and smoother driving. 75kg/m fishplate is suitable for high-speed railway main line rails, thickened design with 8 bolt holes, impact resistance and anti-joint deformation, adapting to high-speed driving. Foreign standard fishplates are designed according to corresponding foreign standard rails, with hole positions, dimensions and thickness fully matched, directly docking international track joint construction.
What are the core material requirements of fishplates and material matching principles with rails?
The core material of fishplates must be the same grade as rails, national standard fishplates are U71Mn/U75V alloy steel, foreign standard are UIC900A/Grade335 material, the strength is equal to rails to avoid uneven stress. Ordinary railway fishplates use U71Mn material with tensile strength ≥880MPa, matched with the same material rails, good plasticity and easy installation. High-speed railway/heavy-duty fishplates use U75V material with tensile strength ≥980MPa, wear resistance and fatigue resistance, bearing high-frequency vibration synchronously with high-speed railway rails. The core principle of material matching is same strength and material, strength deviation ≤100MPa, it is forbidden to match low-strength fishplates with high-strength rails to avoid joint first failure. Material matching requires hardness deviation ≤20HB and chemical element content difference ≤5% to ensure uniform stress on joints without local damage.
What are the core process specifications and bolt torque requirements for fishplate installation?
Before fishplate installation, first clean the rail joint end face and bolt holes, remove rust and debris to ensure the joint fits without gaps and bolt holes are aligned without offset. Attach the fishplate to both sides of the rail joint to ensure the fishplate is centered and symmetrical, the slot fully fits the rail head and rail base without skew and dislocation. Thread the supporting high-strength bolts, install flat washers and lock nuts, pre-tighten in batches in the order of middle to edge to avoid stress concentration from single locking. Fishplate bolt torque is set according to rail specifications, 50/60kg/m rails with torque 600-800N·m, 75kg/m rails with torque 800-1000N·m, foreign standard fishplates set torque according to corresponding standards. After installation, check that the fishplate has no edge warping, joint gap ≤0.2mm, bolts no loosening, and rail joint straightness error ≤0.3mm.
What are the core structural differences between high-speed railway/ordinary railway/industrial mining fishplates?
High-speed railway fishplates are arc thickened structure, the rail head fitting part is with arc chamfer to avoid wheel impact on joints during driving, adapting to high-speed and smooth driving needs of high-speed railways. Ordinary railway fishplates are straight plate conventional structure with thickness 16-18mm, bolt hole positions are symmetrically designed, convenient processing meeting ordinary railway basic connection needs with economical cost. Industrial and mining fishplates are heavy-duty thickened type with thickness ≥22mm, bolt holes are wear-hardened with strong impact and wear resistance, adapting to high-frequency rolling working conditions of industrial and mining. High-speed railway fishplates are matched with insulating bolts and gaskets, the joint insulation meets the standard to avoid circuit interference, ordinary railway/industrial mining fishplates are matched with ordinary bolts without insulation requirements. High-speed railway fishplate joint gap ≤0.1mm, ordinary railway ≤0.2mm, industrial and mining ≤0.3mm, gap accuracy is improved step by step according to driving speed.
What are the common faults and maintenance rectification measures of fishplates in use?
Common faults of fishplates in use include bolt hole wear, body crack, joint loosening, rust deformation and rail joint dislocation, all need timely treatment to ensure driving safety. Bolt hole wear ≥1mm will lead to bolt shaking and locking failure, new fishplates must be replaced immediately, heavy-duty lines upgrade wear-resistant hole fishplates to reduce wear frequency. Fishplate cracks are mostly caused by stress concentration or overload, remove cracked fishplates and replace with new ones, check whether the line load exceeds the standard, reinforce the track on both sides of the joint. Joint loosening is torque attenuation or anti-loosening failure, retighten bolts to standard torque, install anti-loosening washers, inspect torque value monthly and retighten in time. Rust deformation is caused by coating falling off and moisture, derust and hot-dip galvanizing treatment, replace stainless steel fishplates in coastal areas to extend service life. Rail joint dislocation is due to improper fishplate selection, replace adapted fishplates, calibrate rail position, re-install and lock according to specifications.