How many stages has the train operation control system of domestic urban rail transit gone through? Briefly talk about the characteristics of each stage.

Looking back on the development of China's urban rail in recent years, it has gone through the process of "rapid development → suspension of approval → resumption of approval → high-speed and high-quality development". In 2003, "Notice on Strengthening the Construction and Management of Urban Rapid Rail Transit", namely "Document 8 1", with the gradual improvement of the economic level in all parts of the country, urban rail, as the main infrastructure project, has made great contributions to stimulating the local economy. Therefore, as more and more cities reach the standard of "Document 8 1", the application for urban rail approval is gradually followed up. However, in August of 17, Baotou Metro was stopped by the central government because of its own financial problems, and then the Opinions on Further Strengthening the Management of Urban Rail Transit Planning and Construction No.2018 and Document No.52 were issued, with stricter examination and approval conditions, not only for general public budget revenue, regional GDP and urban resident population, for example, the urban general public budget revenue declared by the subway changed from 8/kloc- At the same time, the conditions of passenger transport intensity in the initial stage of the proposed project have been increased, and the urban access threshold of subway and light rail has been significantly improved, so that all aspects of the project have been guaranteed.

Looking back on the past ten years (20 1 1-2020), the operating mileage of urban rail in China increased by about 652 kilometers annually, with an average annual increase of 872 kilometers during the 13th Five-Year Plan period (20 16-2020), that is, during the 12th Five-Year Plan period (20 16544). The operating mileage of urban rail transit in China has reached 7,978.6544 kilometers, far exceeding the previous mileage of 6,000 kilometers in the Thirteenth Five-Year Plan, which fully proves that the new infrastructure of urban rail transit in China has repeatedly exceeded expectations and is currently in a stage of rapid development. Moreover, the rapid development in the future is more driven by "transportation power", "metropolitan area" and "urban agglomeration". It is estimated that by 2025, the operating mileage of urban rail transit in China will reach more than10.5 million kilometers, and the compound annual growth rate in the next five years will be about 13.5%. In the current urban operation, Shanghai, Beijing, Chengdu, Guangzhou-Shenzhen, Nanjing, Wuhan, Chongqing and Hangzhou are major cities with high concentration, with CR5 exceeding 40% and CR 10 exceeding 6 1%. After Document No.52 (65438+2008), the examination and approval of urban rail became stricter, and big cities with strong economic strength and large population flow became the first main force of urban rail construction in China, further boosting the project quality and ensuring the downstream payment of the project.