For example, the northeast corridor (former Pennsylvania RR) under Amtrak’s ownership has 140 lb/yard rails. Believe it or not, a lot of new “light rail” tracks have 115 lb/yd rails, even when they aren’t required to share with freight trains.
Yes.
The train speed is mostly a function of track quality. (also curves and vertical profile)
Trains, even a current ones, are able to travel up to 150mi/h. (Acela top speed) which would be acceptable in the SF to LA distance of about 400 mi. (about 3 hours).
Since the flights takes about 1.5 hour and one has to be there like 1-1,5 hours ahead, and then wait for checking and check out luggage’s, the small seats, the noise of planes.
3 hours of train would be definitely competitive with airlines and beat the cars.
So radical upgrade of existing tracks would be probably quite competitive.
Unfortunately, I doubt that Union Pacific is ready for radical upgrade of their existing tracks.
Without that, Dreamstar could be maybe able to speed up to 30-40mi/h. Clearly uncompetirive with either plane or Car.
So we need this monstrosity of high sped train, which will never happened.