You could argue that China has devolved into a totalitarian state under Xi. There's a lot of corruption surrounding the party's Ministry of Railways, which has led to some perverse incentives to invest (possibly way too much) in HSR and urban metro networks across all of the country. And thanks to the extremely centralized power structure, you have a lot of standardized components used to roll out those networks, making construction cheaper and faster due to economies of scale.

Tldr; China's rail infra is pretty great, especially when so many of its cities are very rough around the edges otherwise.