National Standard Rail Specifications and Applications
- What are the common specifications of national standard rails?
Common specifications of national standard rails are classified by the approximate mass per meter, including 43kg/m, 50kg/m, 60kg/m, 75kg/m, etc. The 43kg/m rail was widely used in the early days and is still used in some branch lines or special lines. The 50kg/m rail has a certain proportion in ordinary railway trunk lines. The 60kg/m rail is currently widely used in Chinese railway trunk lines, which can better meet the requirements of train speed and load. The 75kg/m rail is mostly used in heavy-haul railways and other lines with extremely high requirements for bearing capacity.
- What are the differences in application scenarios for different specifications of national standard rails?
The 43kg/m rail, due to its relatively low bearing capacity, is suitable for branch railways with small traffic volume and slow speed, such as internal railway lines of factories and mines. The train axle load on these lines is small, and this specification of rail can meet the requirements with a lower cost. The 50kg/m rail is suitable for some ordinary railway trunk lines with medium traffic volume and can handle the operation of common passenger and freight trains. The 60kg/m rail is widely used in busy trunk railways. Whether it is a high-speed passenger dedicated line or a large-volume freight trunk line, it can ensure the safe and stable operation of trains with good strength and stability. The 75kg/m rail is mainly used in heavy-haul railways. These railways transport heavy goods and have strict requirements for the bearing and wear resistance of rails. The 75kg/m rail can withstand huge pressure.
- What is the length standard of national standard rails?
The length of 43kg/m rails is 12.5m and 25m. For rails of 50kg/m and above, the lengths are usually 25m, 50m, and 100m. In the laying of seamless lines, 100m rails (hundred-meter fixed-length rails) produced by steel mills are often used, transported to the rail welding factory, welded into 500m long rails, and then transported to the construction site. They are welded into appropriate lengths according to actual needs to reduce rail joints and improve track smoothness.
- What factors need to be considered when choosing the specification of national standard rails?
The designed traffic volume of the railway needs to be considered. Lines with large traffic volume should choose rails with strong bearing capacity. For example, heavy-haul railways choose 75kg/m or 60kg/m rails. The train running speed also matters. High-speed lines have high requirements for rail smoothness and stability, and mostly use rails of 60kg/m and above. The purpose of the line is also a factor. The needs of factory and mine branch lines are different from those of busy trunk lines. In addition, the cost factor should be considered. Different specifications of rails have different prices. Under the premise of meeting the use requirements, try to choose a cost-effective specification.
- What is the relationship between the material and specification of national standard rails?
The materials of national standard rails with different specifications are different. Generally speaking, as the specification increases, the requirements for material strength and toughness are higher. For example, rails of 60kg/m and above mostly use steel containing alloy elements, such as U71Mn, U75V, etc. By adding alloy elements such as manganese and vanadium, the strength and wear resistance of the steel are improved to adapt to greater loads and wear. While some 43kg/m and 50kg/m rails use ordinary carbon steel to control costs while meeting certain strength requirements.