Differences Between National Standard and Foreign Standard Rails and Key Selection Considerations
- What are the main differences in specifications between national standard rails and foreign standard rails?
Common specifications of national standard rails include 38kg/m, 43kg/m, 50kg/m, 60kg/m, 75kg/m. For example, 60kg/m rails are widely used in trunk railways. For foreign standard rails, such as AREA 136RE (about 66.6kg/m) commonly used in the United States and UIC60 (about 60kg/m, but with different dimensional details) in Europe. Due to different railway standards in different countries and regions, the specifications of foreign standard rails are more diverse and complex.
- What are the differences in material composition between the two?
National standard rails mainly use materials such as U71Mn and U75V. U71Mn has a carbon content of about 0.65% - 0.76% and manganese of 0.8% - 1.2%, with good strength and toughness. Foreign standard rails, such as AAR M102 material in the United States, have different composition control ranges from national standard rails. There are differences in the addition and ratio of trace elements to adapt to different railway operating conditions, such as the special requirements for material wear resistance in heavy - haul transportation.
- How to select rail standards according to railway uses?
For ordinary freight railways in China, if the traffic volume is moderate, 50kg/m national standard rails can be selected, which are cost - effective and can meet general load requirements. For high - speed passenger dedicated lines, considering stability and durability at high speeds, 60kg/m national standard rails or higher - strength grade rails are the first choice. For international cooperation projects connecting to foreign railway networks, the foreign standard rail standards need to be selected according to local conditions. For example, in some African regions using European - standard railways, rails that meet UIC standards should be selected.
- What are the special technical requirements for foreign standard rails?
Some foreign standard rails have extremely high requirements for surface quality. For example, the rails for the Japanese Shinkansen have strict restrictions on surface roughness and decarburized layer depth to reduce wear and noise between wheels and rails. Some foreign standard rails have special regulations on low - temperature toughness. For example, the rails used in cold regions in Russia are required to maintain good anti - fracture performance at extremely low temperatures to prevent rail brittle fracture in winter.
- What environmental factors need to be considered when selecting rails?
In high - temperature regions, such as tropical countries, the thermal stability of the rails needs to be considered to prevent rail buckling due to excessive temperature. Rails with good thermal stability and appropriate rail types can be selected. In high - humidity or coastal areas, rails are prone to rust. Attention should be paid to their corrosion resistance. Rails added with corrosion - resistant alloy elements or rails with special coating treatment can be selected, such as some corrosion - resistant rails used in coastal railways in the national standard.