There is a way to physically do HSR that would get San Jose (the Bay Area terminal) to LA Union Stn down to around 2 1/2 hours: Bay Area end as planned (tunnel comes out near Los Banos), straight down I-5, base tunnel through the Tehachapis (with a large widening and high ceiling where it crosses the San Andreas and a few other faults to allow for reconstruction after earthquakes) to around Santa Clarita, then pick up I-5 again into downtown LA. The cost would be huge, and with only 2 stations (each end) it would only handle traffic between the Bay Area and LA ignoring everybody in between. Southwest and United would kill it because it would compete with their California 'shuttle' traffic; it wouldn't compete for much else. It would be dependent on government subsidies if not operation forever.

If you want HSR to be part of a real transportation system, it needs to compete for and provide for intermediate traffic, and has to have reasonable and predictable cost. There might be ways to do that with tunnels near Tejon Pass (insufficient information to be sure, but what there is suggests roughly similar cost to what's now planned), but you would lose the potential for High Desert traffic and a Las Vegas connection and it would make a 2 1/2 hour end/end run iffy.

It's theoretically possible to put a Valley station on a I-5 line (Coalinga?) but the cost of connections to the main cities in the Valley (all on the east side) and inconvenience of connections and transfers would limit traffic potential -- unless you want to bump Amtrak and BNSF up to 110-125mph speeds for regional service AND build HSR. That astronomical cost just headed off to the Restaurant at the End of the Universe.

Having HSR run where the people are makes abundant sense, and is what many of the other HSR systems around the world have done -- it builds traffic in the places it makes sense, and eats United Express' lunch (a good thing from a greenhouse gas and subsidy standpoint!) rather than Southwest/United's (not so great, and those runs are important legs in a nationa system). Downside: the 2 1/2 hour run end/end pretty just becomes impossible (3 hours maybe, 3 1/2-4 more likely even for expresses), but there would be a LOT more riders to support the service and LOT less resistance from Real Airlines.

HSR (and passenger railroads and transit generally) don't cover cost (let alone make money) on passenger-miles. They make it on boardings. That's the only way to keep the return per passenger-mile reasonable without pricing everybody out of the market. Considering the cost to do it "right" fares for SJ-LA on the I-5-direct run would probably need to be at least at airline levels if not higher to avoid a near-total subsidy for all passengers. Frankly, 3 (or even 4 at peak times) hours SJ-LA is competitive with air travel considering security time and transfers (though those thinking that HSR wouldn't also have airport-style security are smoking something interesting), which would allow a couple of intermediate stops. So it's really a balancing act between what would be wonderful and what's simply good and what makes economic sense.

Bump Amtrak up to 110 or better over most of its existing SJ run with the ability to run more trains and a better connection "over the hill") and you might even approach "good enough" meaning competitive with driving for both end/end and intermediate points, considering both time and cost. And you'd still eat United Express' lunch for trips that aren't just in-airport connections to another flight.

Of course, if you strictly interpret the bond act language (which I think was inserted as a poison pill to prevent most of the money from ever being spent), you can't do anything unless it's the 2 1/2 hour trip.

Now back to the discussion of why the BUR station should be moved (which is where this thread started). My opinion: as long as the train schedules are as sparse as they are, the airport needs stations on BOTH lines for adequate service. Right now, the train is convenient if you happen to have flights during peak train times -- but there are large gaps between trains at some times of day (even counting both Amtrak and Metrolink). Having a nearby station on the AV line, and a connector from there running through the airport, the Ventura line station, and on to North Hollywood Red Line would be the ideal situation. Something like that would render LAX useless for trips between LA and northern CA. But since it would be transit or a "monorail" type of peoplemover operation RailPac probably wouldn't care about it.