I was anti-high speed rail until I came to Europe and started using it. Now I'll take a train over a flight unless it's totally impractical not to take the plane. Here's why.
1. Airports are rarely in convenient locations. Rail stations are usually right in the middle of town.
2. It's a colossal pain in the *** to get on a plane - the lines, having your junk felt up by the TSA, the bitchy old women and obnoxious gay guys you have to deal with at the airport, the crappy but very expensive food. At the train station, you're not part of a captive market because it's in the middle of town. You can walk across the street and get something to eat/drink before your train leaves if you want. They know that, so you get much better food and service. No lines. If you buy your ticket in advance, you walk right on. (An attendant verifies your ticket on board after you're seated.) If you don't buy your ticket in advance, you wait in one line, and you don't get sodomized on the fare like you would if you tried to buy an airline ticket at the airport. It's nice to be able to show up 10 minutes before departure instead of 2 hours.
3. Planes are very uncomfortable. The seats are cramped, and you have no leg room. You can fly first class, but you'll pay out the rear. Trains have plenty of room, and even the second class seats are large and comfortable.
4. Airlines lose your luggage. You don't have to check luggage on a train, so it doesn't get lost.
5. You're lucky if you get garbage to eat on a plane. Trains usually have real food if you want it. You'll have to pay for it, but you won't get bent over. You can even get a decent beer if you want.
6. While it takes a lot of government money to run a train system, it takes a lot to run the airlines. The taxpayers build their airports, pay them to fly our mail, and funded a lot of the research that goes into their aircraft.
Having said that, the further you have to travel, the less sense rail makes. Europe and the East Coast of the US are very crowded, so it works well there. However, I think California is probably too spread out to make it viable. Furthermore, this particular rail project seems bogus to me. Even from Riverside, you're looking at a 50 mile drive to Victorville. I think they'd get more interest if it went to (for example) Ontario or a city a little closer to the action.