High Speed Rail?

It's a baby step in the right direction, but I would redesign the entire transit system.

Powertrain, suspension and steering, and computer autopilot need to be separate, standardized units, in a variety of sizes and powers. You rent these as needed.

Passenger cabs are owned by the consumer, and are detachable.

If you want to go long distances. You get your cab loaded onto a flat car on rails, enclosed tube for train optional. You zip to LA at 300mph plus, solar powered train. You cab is then re-attached to another powertrain combo. That can be electric or diesel or gas, depending on your desires and pocket book.

40,000 die each year, many more maimed, incredible costs in dollars and emotions. Only a mad species on a mad planet would keep this up for yet another century.