Do you know the causes and effects of fat edges on rails?
Rail Infrastructure
Do you know the causes and effects of fat edges on rails?
âCauses
1. The track is too rigid, and irregularities on the track cause huge power to the wheels;
2. There is a large difference in vehicle speed through the curve, resulting in eccentric load on the inner and outer rails, or due to improper super-elevation settings;
3. Sliding of wheels;
4. The steel is of poor quality.
âInspection method
1. Visually inspect and use a ruler or depth gauge to measure,
2. Use a profilometer to measure.
âDevelopment results
1. After the fat edge is generated, if it is not repaired in time, it will affect the train operation.
2. Affects track status inspection, including manual static inspection and track inspection vehicle dynamic inspection for track gauge measurement.
3. The fat edge of the rail end of the ordinary joint will affect the rail seam setting effect and cause blind seams; the fat edge of the insulating joint will cause the insulated rail end to be extruded and cracked. Severe fat edge will cause the insulating joint to be connected and the insulation will fail, resulting in Red light band.
4. The sharp edge produced by the point rail will cause the point rail and the basic rail to not be in close contact, causing the switch to fail. When the train passes, the extrusion causes the fat edge between the point rail and the basic rail, which may cause pieces of the point rail to fall off.
âRepair method
1. When the fat edge is larger than 0.3mm, it needs to be repaired. The fat edge of the rail can be processed by grinding (or milling).
2. For fat edges caused by superelevation setting of the curve, the curve parameters should be optimized while grinding rails. It is advisable to adjust the superelevation settings before grinding the rails.
3. Rails that exceed the service limit should be replaced.
âPreventive Action
1. Select high-strength grade rails that match the operating conditions to avoid or reduce the wheel-rail contact pressure stress exceeding the rail yield strength value, which can reduce the occurrence of fat edges.
2. Set the curve super height reasonably to prevent the lower rail from bearing excessive wheel-rail contact compressive stress load.
3. Improve the smoothness of the joint position, improve the elastic foundation under the joint rail, and reduce the impact load when the wheel passes the joint.
4. Periodically polish the rails and joints, repair the rail profile in a timely manner, and optimize and improve the wheel-rail contact relationship.
5. To prevent the fat edge of point rail, the top surface of point rail and the basic rail can be chamfered before the point rail is put on the road. When replacing the tip rail, try to replace the basic rail simultaneously; if it cannot be replaced simultaneously, it is necessary to measure and adjust the reduction value of the tip rail after replacement to avoid premature stress on the tip rail.
Joanie
Mob./whatsapp:008615015909102
Email:inquiry@linkagetrack.com
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