Put a price on carbon emissions and it will happen tomorrow. (or more likely, polarized as it already is, US will start a civil war on the climate change hitting some pockets).

I don't think there is "one thing" and the changes needed are not small.

Oh.. at 600 km/h, China's MagLev already exceeds your top speed request.

@MichaelKutz thanks! I removed that wrong speed from my post.

The non-invention of the airplane?

@MichaelKutz this is the real answer, the lack of HSR in the US isn't some weird quirk it's a function of population distribution, geography and demand incentives. To connect Chicago to LA and the rest of the west coast means going through literally 1000's of miles of land where basically no one lives and then going through difficult terrain. There is absolutely no way you can do that cheaper than it is to connect them with planes -- it's not even close. It works in Europe because Europe has a bunch of high density population centers located in close proximity to one another.

just look at the nightmare system they are building in CA for a case study at how off the rails these things go. and that's for a route that would actually make sense given the demand and population centers along the route. Compare to a CHI to Denver route where you have 800 miles of track through two states with a combined population that's barely double Paris. The demand for such a route simply doesn't justify a project whose cost would easily be > 200 Billion in initial costs alone.

@AdrianColomitchi Washington State is a pretty blue state (60/40 dem in last election) and their 2016 ballot initiative, where the pro-carbon-tax side had double the funding of the opposition, had their ballot initiative for carbon tax defeated by a 60/40 vote.

train cost < plane cost cost to who? the person who buys the ticket? or to the train or airline company?

@eps, The problem in the US isn't LACK of density per se. In Florida, you could EASILY draw HSR routes where there's a dense urban area every 15-25 miles or so. The thing is, in other countries, they usually HAVE (deliberately) vacant open land between city centers. So... they can dig an expensive 2-5km tunnel, then run for 20-30km across open countryside to the next city. In the US, the development between city centers might not be dense... but almost every square inch is occupied by single-family homes and strip malls that would have to be bought & demolished at STAGGERING cost.

@Bitbang3r Ideally, you'd want at least 200 or 300 km between stations of high speed rail, and have regional trains connect those hubs to the smaller cities. Smaller distances gradually diminish the advantage of being high-speed.

@MichaelKutz Seems the fastest commercial speed of the Shanghai maglev is 431 km/h rather than 600. Which is more than the conventional TGV at 320 km/h (still holds world record on rail at 574.8 km/h for reference, and actually went faster on unrecorded attempts). TGV could operate faster, but the cost would be simply too costly for the marginal gains at the scale of France. Maglev is likely more viable at higher speeds because of the maglev-ing, but I'm no expert on maglev.

@GlenYates Great idea - and the aeroplane would have been delayed if the bicycle were delayed, which also would have crippled the emergent feminist movement at the time resulting in delays in emancipation of women.

Shouldn't it be "tiniest" instead of "teeniest"?

@Kaddath: In American English, at least, either works. Ask on the English Language site if you want to know more.

@Bitbang3r But houses are destroyed for highways all the time (eg a million people have been displaced for highways just between '57 and '77). I would assume that a high-capacity railroad would displace fewer people than a highway.

@Michael: Cost would be eventually transport cost per seat per distance, and that obviously for the transport company. As long as the market is functional, ticket prices would then be that plus a bit of profit.

@jamesqf thanks, that's why I asked, english is not my mother tongue and I had never seen this version

The US's preeminence in flight and it decades long push to keep it's global leadership in the airline industry is the primary thing that killed HST's chances here. General consensus now is that the only viable place for HST is the NY to DC corridor, which is also among the most expensive property (and most litigious).

The top and bottom maps also completely ignore the Michigan situation. The state bought the Porter IN-Kalamazoo-Detroit line and is incrementally developing it into HSR. They promptly bumped it to 110 mph (most lines are 70-79) and they are eliminating grade crossings. So HSR is definitely going that way and serving the many cities enroute (Kalamazoo, Battle Creek, Jackson, Ann Arbor). Be silly to put another HSR on the parallel Porter-Toledo route.