> "The line costs between 150 million yuan and 250 million yuan per kilometer, making it highly economical compared to subways and light rail, which cost up to 800 million yuan and 300 million yuan per km respectively"

Putting a viaduct in the middle of nowhere, where eminent domain committed by a totalitarian state lets you get access to very cheap land usage, is not a fair comparison with having to dig holes in a high-density city.