Rail Classification and Selection Criteria
- What are the common specifications of national standard rails?
Common specifications include 38kg/m, 43kg/m, 50kg/m, 60kg/m, 75kg/m. The 38kg/m rails were used in some branch railways in the early days and are now used less and less. The 50kg/m rails are common in ordinary trunk railways and can meet the requirements of medium traffic volume and speed. The 60kg/m rails are widely used in high - speed and heavy - haul railways because of their better bearing capacity. The 75kg/m rails are mainly used in heavy - haul railways with extremely large traffic volume, such as some mining area railways.
- What are the main standard systems of foreign standard rails?
The British standard has the BS series, such as models 90A, 80A, etc., which are often used in the railways of the UK and some Commonwealth countries. The German standard is mainly the DIN series, such as models A45, A55 under the DIN536 standard, which are widely used in Germany and some parts of Europe. The International Union of Railways has formulated the UIC series of standards. Models such as UIC60 are used in the railway construction of many European countries. The Japanese standard is the JIS series. Its rail standards are applicable to the railways in Japan and have high requirements for the accuracy and surface quality of the rails.
- How to select rails according to railway operation conditions?
For high - speed passenger dedicated lines, in order to ensure the stability and safety of high - speed train operation, rails with high strength and good smoothness should be selected, such as national standard rails of 60kg/m and above or foreign standard rails that meet the corresponding high - speed standards. For example, UIC860 is used for high - speed lines in Europe. On heavy - haul freight railways, considering the large axle load of trains, rails with strong bearing capacity should be selected, such as 75kg/m national standard rails or medium - heavy rail models in the German standard, such as A75, etc. For ordinary passenger - freight mixed railways, a comprehensive assessment can be made according to the traffic volume and speed. Generally, 50kg/m or 60kg/m national standard rails can meet the requirements.
- What are the differences in the performance of rails with different materials?
Ordinary manganese - containing rails, such as the commonly used U71Mn material in China, have good comprehensive performance, with a relatively balanced strength and toughness, and are suitable for most railway lines. Copper - containing plain carbon steel rails have a certain improvement in corrosion resistance and are more suitable for use in railways in humid or coastal areas. High - silicon copper - containing steel rails not only have good corrosion resistance, but also have relatively outstanding wear resistance and can be used in sections of lines with severe wear. Manganese rails have a relatively high manganese content, which improves the strength and hardness of the rails and can withstand greater loads, but the toughness may be relatively reduced.
- What considerations are there for the curve radius of the track when selecting rails?
In small - radius curve sections, the lateral force on the rails is relatively large, and the rails need to have better anti - bending ability and wear resistance. At this time, rails with higher strength and more wear - resistant materials can be selected. For example, in the small - radius curves of some mountain railways, specially treated 60kg/m rails or specific models of foreign standard rails will be selected. In large - radius curve sections, the requirements for the lateral force of the rails are relatively low, but their smoothness still needs to be ensured. Generally, rails of the same specification as the straight section but of higher quality can be selected to reduce the vibration and noise when the train passes.