China is not as hyper centralized as you think, the regions have quite a bit of power over policy as long as they deliver results. Some things are centralized, maybe to many in China. But for things like High Speed rail, such centralization is not bad. Not everything needs centralization but some kind of centralized decision making is need for grand decisions.

The US does this hilariously wrong. Like giving each state money for public metro system and then each state implements a unique incompatible solution that really only differs slightly from the alternative. In a competitive private market that fine, industry standards can emerge. But in terms of metro system that a country only builds very rarely having the system be the same between metros makes a lot of sense.

Its not like these are experimental concepts that nobody in the world knew about already.