Fishplate Specifications and Connection Requirements
- What are the common specifications of fishplates?
The specifications of fishplates correspond to the specifications of rails. Common ones include fishplates matching 50kg/m and 60kg/m rails. The length of the fishplate matching 50kg/m rails is about 790mm, and the thickness is about 26mm; the length of the fishplate matching 60kg/m rails is about 820mm, and the thickness is about 30mm. The specifications of foreign standard fishplates match foreign standard rails. For example, the fishplate matching UIC60 rails has dimensions and hole positions that meet UIC standards. The number and spacing of bolt holes of fishplates with different specifications are also different to meet the corresponding rail connection needs.
- What are the connection methods between fishplates and rails?
The main method is bolt connection, which is realized by passing bolts through the bolt holes of the fishplate and the rail and tightening the nuts. This method is convenient for disassembly and facilitates the maintenance and replacement of rails. In some special sections, such as the buffer zone of seamless lines, a combination of welding and bolt connection may be used. First, welding is used to enhance the integrity, and then bolts are used for auxiliary fixing to improve the strength and stability of the joint. In addition, for some temporary tracks or light - duty tracks, riveting may also be used, but the application is relatively less.
- What are the requirements for bolts when connecting fishplates?
The specification of the bolt must match the bolt holes of the fishplate and the rail. For example, M24 bolts are commonly used for fishplates of 60kg/m rails. The material of the bolt should have high strength, and 8.8 - grade or 10.9 - grade high - strength bolts are generally used to ensure the tightness of the connection. During installation, the tightening torque of the bolt must meet the regulations. The torque of the fishplate bolt for 60kg/m rails is usually between 600 - 800N·m, and it must be tightened symmetrically and evenly to avoid uneven stress. The bolts also need to be anti - corrosion treated, such as galvanizing, to improve their service life.
- What precautions should be taken during the installation of fishplates?
Before installation, check whether the bolt holes of the fishplate and the rail are aligned, and there must be no debris in the holes to ensure that the bolts can pass through smoothly. The contact surface between the fishplate and the rail should be cleaned, and there should be no rust, oil, etc., to ensure close fit. During installation, the fishplate should be placed in the middle of the rail joint, and the extending length on both sides should be uniform. When tightening the bolts, follow the order from the middle to both ends in stages to avoid deformation or uneven stress of the fishplate caused by one - time tightening. After installation, check whether the fishplate is closely attached to the rail, and the gap must not be greater than 0.3mm.
- How to inspect the quality of fishplate connections?
The tightening torque of the bolts can be checked by rechecking with a torque wrench to ensure that the torque of each bolt is within the specified range. Observe the fitting situation between the fishplate and the rail, and check the gap with a feeler gauge. If the gap is too large, it indicates that the connection is not tight, and the fishplate needs to be re - tightened or replaced. Check whether the fishplate has cracks, deformation and other damages, and methods such as magnetic particle flaw detection can be used to detect internal defects. After the train passes, check the status of the fishplate and bolts again to see if there is loosening or displacement, so as to ensure stable connection quality.