China can do it because they have a command economy and the government can just take property to do what it wants.
To do this in the USA you'd have a thousand different emminent domain claims to get through, at least some of which will be contested, you'll need to pay the property owners fair market prices for the land you are taking, there will need to be environmental impact studies, planning commission approvals, fights with every interested locality over station locations and ammenities and how many trees will be cut down. China doesn't have to worry about any of that they just do it.
To do this in the USA you'd have a thousand different emminent domain claims to get through, at least some of which will be contested, you'll need to pay the property owners fair market prices for the land you are taking, there will need to be environmental impact studies, planning commission approvals, fights with every interested locality over station locations and ammenities and how many trees will be cut down. China doesn't have to worry about any of that they just do it.