1. Climbing derailment: there are foreign objects with high hardness in the gantry crane trolley track. When the large wheel passes by, it climbs the foreign objects, causing the bottom of the wheel flange to be higher than the rail surface. After pressing the foreign objects, the wheel tread and the rail surface are misaligned, and the wheel flange is directly pressed on the rail surface or left the track, which is called climbing derailment.
2. Rail gnawing and derailment: there is a problem with the matching of the large and small balance beams of the crane or the pin shafts of the trolley, or there is a height difference between the sea and land side rails, the center of gravity of the gantry crane changes, and the crane travels offset, resulting in the interference between the wheel flange of the crane and the rail, rail gnawing, abnormal wear of the wheel flange and the rail to a certain extent, and the wheel flange directly slides onto the rail tread, which is called sliding on derailment.
3. Jump on and derail: when the gantry crane cart is traveling at full speed, the unilateral wheel gripper or brake suddenly releases and fails, and suddenly clamps the unilateral wheel. At this time, the movement trend of the crane changes from straight line to rotary movement. Under the action of inertia, the wheel jumps on the track and derails, which is called jump on and derail.
4. External force derailment: the derailment occurs when the gantry crane encounters a large lateral force impact when traveling; Or under the action of strong external forces such as typhoons and strong gusts, the large wheels are derailed by external forces.
