1. The rail joints are wrong
The two-strand rail joint of the line should generally adopt the relative type. The outer strands of the curved lot should use standard-length rails, and the inner strands should use factory-made shortened rails to adjust the position of rail joints. The remaining small amount of phase error should be adjusted within the curve (in the straight line if there is difficulty) using the rail length error amount. Straight sections should be paired according to the amount of rail error. The difference in each rail should generally not be more than 3 mm, and should be offset before and after, left and right. On two rails, the maximum cumulative difference shall not be greater than 15 mm. When laying non-standard length rails or reused rails, and shortening rails without factory production, the rail joints can adopt the phase staggered type, and the phase misalignment amount shall not be less than 3 m. When the straight length between two curves with a cross-staggered joint is less than 300 m, the straight segment can also be mistyped. The short rails inserted individually when using the staggered type should be laid on the straight line at both ends of the curve, and the inner strands of the curve can be laid under difficult conditions.
2. Insert individual short rail regulations on the line
Short rails are inserted individually on the line, which shall not be shorter than 6m on the main line and 4.5 m on the station line, and shall not be inserted two or more in a row. The permissible speed of individual plugged short rail lines shall not be greater than 160 km.h.
3. There must be no position for rail joints
(1) Within the full bridge range of the small bridge with the clear bridge deck;
(2) Within 2 m of the end of the steel beam, the temperature expansion joint of the arch bridge and the vault within 2 m before and after;
(3) Within the temperature span range of the steel beam equipped with a temperature regulator;
(4) on top of the beam of the steel beam;
(5) Within the paving range of level crossings.
If the rail joint is exactly in the upper position and a 25 m length standard rail is laid, a 12.5 m length standard rail can be inserted to adjust the joint position; When laying a standard rail with a length of 12.5 m, it can be replaced with a standard rail with a length of 25 m to adjust the position of the joint, or the joint can be tightened and frozen or welded with high-strength bolts after squeezing the rail seam. When it is difficult, it is allowed to insert individual short rails to adjust the position of the joint.