Fishplate Type Selection and Installation Specifications
- What are the different application scenarios of ordinary fishplates and special-shaped fishplates?
Ordinary fishplates are suitable for the straight connection of rails of the same type and specification, such as 60kg/m rails with 60kg/m ordinary fishplates, which have a simple structure and are easy to install. Special-shaped fishplates are used for transition connection of rails of different specifications or in turnout areas, such as connecting 50kg/m and 60kg/m rails. Their special shape design can adapt to the cross-sectional dimensions of different rails to ensure smooth transition.
- What are the considerations in the design of the number and position of bolt holes in fishplates?
The number and position of bolt holes in fishplates need to be determined according to the stress of the rail, and generally, there are 4 - 6 bolt holes at each end. The hole spacing is evenly distributed to balance the stress on the bolts and avoid stress concentration. For example, the 60kg/m rail fishplate is provided with 4 bolt holes at each end with a hole spacing of 100mm, ensuring that after the bolts are tightened, the fishplate is closely attached to the rail and evenly transmits the load.
- What are the requirements for rail gaps when installing fishplates?
When installing fishplates, a certain gap (expansion joint) should be reserved at the rail joint to cope with the thermal expansion and contraction of the rail. The gap in ordinary lines should not be greater than 18mm in winter and not less than 10mm in summer; the gap in seamless line sections is reserved according to the design requirements, generally 6 - 8mm. Excessively large or small gaps will affect the stress of the fishplate and even cause track deformation.
- What are the differences in installation torque of bolts for fishplates of different materials?
The installation torque of bolts for Q235 steel fishplates is generally 300 - 350N·m. Because of their low strength, excessive torque is easy to cause deformation. The bolt torque for low-alloy high-strength steel fishplates (such as Q345) needs to reach 400 - 450N·m to ensure sufficient preload and firm connection. During installation, the torque value corresponding to the material should be followed to avoid looseness or over-tightening.
- What are the inspection items after fishplate installation?
Check whether the fishplate is closely attached to the rail, measure the gap with a feeler gauge, which should not be greater than 0.3mm; check whether the bolts are complete and tight, and the torque value meets the requirements; observe whether the fishplate has cracks, deformation and other defects; measure whether the gauge is within the allowable range (±2mm). Timely handle the found problems to ensure the quality of joint connection.