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Application of line laser sensor and laser displacement sensor in railway welding -2D/3D

Many years ago, when we were in the middle of a train, we couldn’t get rid of the noise of “dangling and jingle”. The reason is that it is subject to the technical level at that time. In order to prevent the deformation of the rail caused by thermal expansion and contraction, only gaps can be left between the rails, which greatly reduces the running comfort and safety of the train.
Today's high-speed trains can reach speeds of more than 300 kilometers per hour. Railroad tracks can no longer leave any gaps, even slight deviations in straightness, which can lead to major safety hazards. The rails cannot be extended indefinitely when they leave the factory. How to quickly connect two sections of rails, automatic welding, and how to detect the quality of weld grinding after welding have become a problem for railway engineers.
The seamless welding technology can make the welding points almost invisible between the two sections of the rail, and the transition is natural. On the high-speed rail, the "jingle" sound will become history. After the high-speed rail is laid, the technicians will use advanced welding technology to weld and polish the rails. A strip of 500 meters long and weighing 30 tons is welded into an extra long seamless line to achieve a track paving. There is a soft connection at the expansion joint, and there is reserved space for expansion after being heated. I can't see an interface, it's like two complete rails going through. Such high-precision technology can guarantee the stability of driving.
The traditional rail welding uses the aluminothermic method, which is actually a method of welding the rails with an aluminum thermal reaction. In other words, steel is welded on site, and then molten steel is injected into the gap between the two rails to achieve the welding effect.
Expression of aluminothermic reaction: 2Al+Fe2O3=2Fe+Al2O3 (reaction conditions are high temperature)

Further reading

Exhibitor: Micro-Epsilon Messtechnik