I wonder if, for the cost spent on CPU-and-engineer-driven research and development of autonomous cars, if we could have had nationwide autonomous rail rolled out.
Nope, requires a sane society that gathers around and does whats best for the collective whole. What we have, however, is a kleoptocracy, and being as such, the opportunity to extract more wealth, faster, and easier, existed with selling the promise of autonomous vehicles. If the same incentives existed for autonomous rail, it would have happened already.
Let’s not be so cynical here. No amount of mustache-twirling evil robber barons would change the fact that for any nationwide rail system to be useful at a last mile, billions (if not trillions, if we’re talking coast to coast) of dollars of existing real estate and infrastructure would have to be bulldozed, or else you end up with California’s joke of a Central Valley rail that will never connect Los Angeles to San Francisco and recreate the Shinkansen miracle between Tokyo and Osaka.
In other words, the problem is not a matter of engineering (it can be built) or finance (it can be funded) - it’s politics.
> existing real estate and infrastructure would have to be bulldozed,
You mean like they've done with every beltway and interstate? They claim eminent domain, take whatever strip of land they need from you, and bulldoze anything in it's path to build nice fancy exits full of the same features: a few hotels/motels, gas stations, couple of fast food chains, and, perhaps, if you are fancy enough, a strip mall with a Department store, Sporting Goods, and a fine dining establishment from one of America's most recognized brands: Bloomin' or Darden
There was a push for something like that and it would have been great...it fell afoul of NIMBY and Toll road haters.
https://en.wikipedia.org/wiki/Trans-Texas_Corridor
Everyone in Austin hated SH-45 & 130 when they were built, they were practically empty for a few years to my delight as I could travel the entirety of Austin in a fraction of the normal time even during rush hours. After MOPAC was added residents began to see the light and the tollways are now congested. Many are regretting their opposition to Perry's lost/last road project but, that train has left the station unless Elon can get the Boring project going or Virgin is able to implement their version of Hyperloop. Hell, I'd have settled for elevated wire gondolas over the roads, works well enough for Australia.
Not for passengers. You still need conductors, if for no other reason to be the equivalent of flight attendants (there for extremely rare safety incidents -- deaths per passenger mile are higher for trains than planes -- to manage unruly passengers, etc.)
> On December 29, 2020, FRA announced that PTC technology is in operation on all 57,536 required freight and passenger railroad route miles, prior to the December 31, 2020 statutory deadline set forth by Congress.
I suspect the OP may be more interested in nationwide, convenient, affordable, automated passenger rail.
Which in the US is possibly (?) several orders of magnitude more in terms of capital investment compared to both electrifying the entire ICE fleet and automating it.
The majority of the costs of passenger rail is in the land-costs of placing those statins (and rail-lines) somewhere important.
The US Freight Rail network is just the right place to deploy this technology right now. We may have crappy passenger systems, but our freight is world class.
EDIT: It should be noted that PTC sensors cost $50,000 per train. But each train costs $2+ million, so the PTC sensors aren't that much compared to the overall system. The idea of having a similar suite of $50,000+ sensors / radios on every car is clearly too costly in contrast.