② Heavy rail. According to the type of steel used, it can be divided into: ordinary manganese steel rails, copper plain carbon steel rails, high silicon copper steel rails, copper rails, manganese rails, silicon rails, etc. There are mainly three types: 38, 43, and 50kg. In addition, there are 45kg rails used on a few lines, as well as 60kg rails used on high volume and high-speed lines. GB2585-81 specifies the technical conditions for 38-50kg/m steel rails in China, and their dimensions and codes are shown in Table 6-7-10
