"The only things stopping this is ignorance.."
Yeah, @i8thecat4-- you seem pretty ignorant of both the engineering challenges in the Los Angeles Basin (where the picture above was taken -- BTW, 4% grade right there at the pass between Mulholland and Sunset... not that great for rail), and the politics - read:public money deployment in California.
But feel free to comment more when you get some edumacation in these topic areas.