The installation of the rail pad is a key process in track laying, and its standardization directly affects the stability of the track structure. The installation must follow the principle of "precise positioning, tight fit, and uniform force". The specific process is as follows:
Basic preparations must be made before installation. First, clean the rail surface of the sleeper to ensure that there are no debris, oil stains, and protrusions. Use a grinding tool to deal with burrs to control the surface flatness error within 1mm. At the same time, check the specifications of the pad to confirm that its size matches the rail model (such as 60kg/m rails corresponding to 180mm wide pads), and check whether the material meets the design requirements (rubber pads need to be checked for cracks, and polyurethane pads need to be confirmed to have elasticity standards).
The core installation steps must be strictly controlled. The first step is to position and place the pad symmetrically along the center line of the sleeper to ensure that the edge of the pad is aligned with the edge of the rail surface of the sleeper, and the deviation does not exceed 2mm. For curved track sections, the pad angle needs to be adjusted according to the curve radius to ensure that the arc of fit with the bottom of the rail is consistent. The second step is to place the rails in place. Use a track lifter to slowly place the rails on the pads to avoid hard hitting that may cause the pads to shift or break. After the rails are in place, check the contact area between the rails and the pads, which must reach more than 90%, and the local gap must not exceed 0.5mm.
Tightening and adjustment are the key links in installation. When installing fasteners, the bolts must be tightened step by step according to the principle of "diagonal symmetry". The initial torque is controlled at 60% of the design value (usually 180-220N・m). After the rails and the pads are fully fitted, tighten them to the standard torque (300-350N・m). For height adjustment pads, ensure that the number of superimposed layers does not exceed 3, the total thickness does not exceed 20mm, and the top layer must be a rubber pad to ensure elasticity.
A comprehensive inspection is required after installation. Use a feeler gauge to check the gap between the pad and the sleeper and rail to confirm that there is no through gap; use a torque wrench to re-tighten the fasteners to ensure that there is no looseness; finally measure the track gauge and level, and only proceed to the next process after passing the test. When installing in a low-temperature environment, the pad needs to be preheated in an environment above 5°C in advance to avoid affecting the fit due to hardening of the material.
GNEE RAIL is a professional trading company focusing on the export of railway fasteners, committed to providing reliable rail connection products for global railway construction projects. The main products include a full range of railway fasteners such as various spring clip fastener systems, sleeper bolts, anti-loosening washers and insulating components, which are suitable for various application scenarios such as conventional railways, heavy-duty railways and urban rail transit.