The fantasy map actually was at Amtrak's web site: [
media.amtrak.com]
If there weren't Interstate Highways, I could see an 8-hour overnight Auto Train run from LA to PHX on a fully double-tracked (with a few triple or quad segments) UP. But that's an alternative universe; the one we're living it has airplanes and freeways and cheap fuel.
And the number of people who would ride a train between the Basin and Calexico is likely small enough to justify only buses - which could be run several times a day instead of perhaps once for a train given the costs involved. And which probably already do run (Greyhound or some regional bus line). Yes, if a train ever makes it to the Coachella Valley, it's probably worth looking at an extension; if nothing else, it would give SCAG an excuse to spend a little money in Imperial County. But not until then.