What is a seamless rail?
A continuous welded rail is a long rail line made by welding standard length rails, also known as a welded long rail line. It is named because the long rails have no rail seams.
Types of seamless rails Seamless rails are divided into two types: temperature stress type and thermal stress type. At present, most countries in the world use temperature stress type seamless rails.
A seamless rail refers to a line where rails are welded together, called a welded long rail line. Because there is a huge temperature force in the long rails, it is also called a temperature stress type seamless rail. According to the length of the welded long rails, there are ordinary seamless rails and cross-section seamless rails. The length of the welded rails of the former is generally about 1 to 2 km. 2 to 4 standard rails are set between the two long rails and connected to the long rails in the form of ordinary rail joints to form a buffer zone.
Although it reduces the rail joints, there are still rail joints in the buffer zone. The seamless line across the section is a welded long rail that runs through the entire section and is welded to the station turnout. The seamless line is laid on the bridge. The automatic block section uses high-strength insulating joints, which cancels the buffer zone between the long rail and them, eliminates the rail joints, and completely realizes the seamlessness of the line.
There are expansion zones with a certain amount of expansion and contraction at both ends of the long rails of the above two seamless lines, which are generally 50 to 100 meters long, and the middle part is a fixed zone with no expansion and maximum temperature force. Different from the above two seamless lines is the release temperature stress type seamless line, which is divided into automatic release and regular release. The former is to set expansion regulators at both ends of the welded long rails to automatically release the temperature force in the rails. It is mainly used in lines on high-speed railways and bridges.
The latter is to adjust and release the temperature force inside the rail 1 to 2 times a year. When releasing, loosen all the parts on the welded long rails to allow it to expand and contract freely, release the internal temperature force, and tighten and lock all the fasteners under certain rail temperature conditions. It is mainly suitable for cold areas with large annual rail temperature differences. However, since the release of temperature stress is rather complicated, it is rarely used.
