Why? Just build more trains any train infrastructure is so much better than cars, they barely need improvement, they just need to be built
On the battery front, using car-style or truck-style EV battery modules would be more robust and would reduce cost by somewhere in the order of 50%.
Instead, most trains still use induction motors (this is the high pitch whine you hear) and many train battery designs use industrial style rack mount batteries, with screw terminals, controlled by a massive PLC cabinet. In eMobility the controls are handled by a small safety-rated microcontroller.
The power system after the battery is similar to older model electric vehicles.
(There will be a battery for lights etc.)
[1] https://www.railjournal.com/in_depth/velaro-evolution/
[2] https://www.ew.tu-darmstadt.de/media/ew/rd/ew_vortraege/0305...
a) it works better in a densely populated territory,
b) but the more people around, the more NIMBY cliques to throw sand into the permiting process, usually abusing environmental protections to do so.
If the new Trump administration defangs NEPA reviews just a bit - and I see no evidence that the original intent behind NEPA was to delay everything everywhere by decades - it might help, but a powerful YIMBY movement would be even better.