Blue state America, at least. Around here we routinely do projects on time and budget.
Might be as much a scale problem, are there any Red state America projects being done on vaguely similar scales, with, say, a billion dollars as a minimum baseline?
Can't say much for America, but in the UK our own HS2 high speed rail line, which probably won't be too far longer than 200 miles of track in total is projected to cost £40bn, with some suggestions that the true cost will be closer to £80bn.
Conversely we're also building a new west-east railway across/beneath London that seems to be going fairly well for about £15bn.
High speed rail is just a hugely expensive thing to get built in the developed world it seems.
The question is why? If China can build 10,000 miles of HSR and the developed world can't build 400 miles, won't there be an infrastructure penalty at some future time?
Spain has built 1500 miles of HSR so it seems that the extreme high cost is avoidable.
I'd blame politicizing infrastructure projects and (related) listening too much to NIMBYs. In China, they care much less. And probably for the better; infrastructure is a public good. At some point you have to tell someone to suck it up and take one for the team.
Two major drivers of the cost, as I understand it, are geography and geology of the region and existing land values, especially near the termini (eminent domain, in the US, requiring fair compensation to existing landholders.)
There's also non-cost factors involved with the PRC: for a land based empire like their's, internal lines of communication are critical, and since 1866 Prussia has shown the utility of railroads for that. Faster ones are obviously better, modulo how much heavy equipment you might need to move as well (for a lot of the PRC's issues, lightly armed troops are just fine).
Might be as much a scale problem, are there any Red state America projects being done on vaguely similar scales, with, say, a billion dollars as a minimum baseline?