超大城市，正在拼命建“第二高铁”

Core Viewpoint - The article discusses the necessity and benefits of constructing second high-speed rail lines in major Chinese cities to alleviate congestion and meet increasing passenger demand, while also enhancing connectivity and economic development in surrounding areas [8][18]. Group 1: Reasons for Building Second High-Speed Rail - Major cities like Beijing, Shanghai, Guangzhou, and Shenzhen have already established high-speed rail networks over a decade ago, but the demand for passenger transport continues to grow, leading to capacity constraints [9][12]. - The existing high-speed rail lines are often saturated, with peak periods experiencing ticket shortages, necessitating the construction of additional lines [12][15]. - Upgrades to high-speed rail technology are also required, with a shift from 200 km/h to 350 km/h and aspirations for 400 km/h operations, as seen in the Chengdu-Chongqing line [17][18]. Group 2: Beneficiaries of Second High-Speed Rail Expansion - The second high-speed rail lines are designed to connect major cities while also addressing the needs of less accessible regions, thereby filling gaps in the current high-speed rail network [20][21]. - Unlike the first high-speed rail lines, which primarily connect major urban centers, the second lines often take more circuitous routes to cover additional areas, benefiting smaller cities and regions [22][30]. - The planned Guangzhou-Shenzhen second high-speed rail will connect major airports and extend to Hong Kong, enhancing regional connectivity and economic opportunities [24][30]. Group 3: Future Considerations for High-Speed Rail Expansion - China's high-speed rail network has reached a significant milestone, with 81.5% of the "eight vertical and eight horizontal" network completed, covering 97% of cities with populations over 500,000 [31]. - Future high-speed rail projects will need to consider economic viability, population density, and strategic importance, as many existing lines struggle with debt without sufficient passenger support [33][34]. - The focus will shift towards expanding high-speed rail connections between major cities and strategically important areas, marking a transition from large-scale construction to maintenance and efficiency [33][34].