Trains aren't that great of an idea for long-haul intercity transit in the US. The distances in the US are pretty big outside of a few pockets of European or Japanese style population density. Airplanes are just better at a certain distance.
I mean, you could have had this for a long time already if there were political will. This newly unveiled Chinese train is based on decades old German tech. They tricked Siemens into building them a "test track" in Shanghai ages ago, with the promise of giving them a contract for longer routes. Now they have the tech and plan to build it themselves.
Btw, other countries determined the maglev tech to be uneconomical. I think India and Saudi Arabia and some other places were interested but ultimately nothing became of it.
I was talking generally about HSR, rather than specifically about maglev.
Maglev is complex because:
* it guarantees you can't run services beyond the limit of the new-built track,
* the extra speed comes with higher operational costs (because drag, so you need the time saving to increase modal shift), and
* higher construction costs (to get the higher speeds, you need to build it with very large radii corners, which limits your ability to choose one's route to minimise significant structures; and if you want city-centre stations, you have no choice but to build a new line all the way in, and it turns out that acquiring land in cities is expensive).
I wouldn't _totally_ write off maglev, but there are relatively few corridors which align to make all of this worthwhile.
Maglev at high speeds is cheaper operating costs than normal rail. (normal rail - in tests - has gone just as fast as existing maglev (not this future advance, what is running in production service) The limit to normal rail is actually the power supply (overhead wires) and not the wheels on steel rails. However as you go faster maglev operating costs are cheaper than normal rail at the same speed (more than slower speed normal rail). Also maglev needs less track maintenance which is a large advantage in operating costs.
I mean the record speeds for maglev and steel wheel trains aren't far apart — 603 km/h v. 574 km/h. My understanding is the limits on steel wheel trains in practice are managing airflow on ballasted track (as the airflow can pick up lose ballast and propel it into the train or anything else nearby) along with pantograph-catenary contact as you mention.
My understanding about maglev operational costs is that the energy consumption of each service is higher (due to the need to maintain the electromagnets, which end up consuming more energy than is used to overcome the rolling resistance of steel-on-steel), though the overall operating costs are hard to judge (especially when the only operational line is both short and there is little in the way of public data about its costs).
I wonder if you could beam power to an airplane instead, or maybe even have a low-flying airplane touch electrical wires. An airplane with no battery -- solves a lot of the Maglev problems.
Touching electrical wires is the limit to existing HSR - you can only go so fast before you run into problems. I don't know if they can be engineered out.
I don't know if beaming power is practical. Tesla was working on it long before we were born.