This is from the California High Speed Rail Authority or other proponents of the project so take it with a grain of salt but if half of this materialized it should ameliorate the costs somewhat:
http://en.wikipedia.org/wiki/California_High-Speed_Rail
The CHSRA projects that construction of the system will create approximately 150,000 construction jobs and 450,000 permanent jobs[4] by creating new commuters that will use the system.
Proponents of high speed rail claim the Los Angeles-San Francisco will generate a net surplus of US$2.23 billion by 2023, although critics[who?] point to the significant losses at Amtrak, Caltrain and other similar services to show that these profits may not materialize. Amtrak's high-speed Acela Express service, however, generates an operating surplus[18] that is used to cover operating expenses of other lines.
Since the trains will be completely grade-separated, there is no threat of interfering with automobile and pedestrian traffic. The project also involves grade-separation for existing rail lines with which it will share rights-of-way along part of its length, further improving safety on these lines and eliminating car traffic delays.
Since high-speed trains (based on fossil fuel electricity generation) use one-third the energy of airplanes (per person) and a fifth of that used by cars (with one person),[19] California High-Speed Rail will also eliminate 12 billion pounds of greenhouse gas emissions each year by off-setting passenger car and airplane use. This is the equivalent of removing more than one million vehicles from the state's roads and freeways. It will also lessen California's dependence on foreign oil by up to 12.7 million barrels per year.
The CHSRA projects that the system will "alleviate the need to spend more than $100 billion to build 3,000 miles of new freeway, five airport runways, and 90 departure gates."[4]
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