Imagine what it would be like speeding up the scenic California coast, making it to San Francisco quicker than the "quick and easy" flights often advertised. Many would benefit from this.
With the bump in population for the high speed rail, there would be less use of the interstates or airplanes for travel. If this traffic reduces, there will be less need for road and airport improvement. It is estimated that Americans will pay $100 billion for these improvements through tax money over the next 20 years (Billitteri). In contrast, a comprehensive system of high speed rails connecting all major metropolitan areas will only take $42 billion (Billitteri). Though this is still on a grand scale, we would overall be paying less. If only in California, it would only cost a fraction of that. It is true that a high speed rail would have to be subsidized, meaning that it takes in money from the government and our taxes. However, $8 billion of the stimulus plan will go to high speed rails (Kopp), with $2.25 billion of this slotted to go specifically to California (United States). Also, if we all use high speed transportation, the income from ticket sales will support the system altogether. This would lessen the need for subsidizing, in essence making it self sufficient. Another potential problem is that our tickets would be too expensive, as it would make sense to drive to San Francisco or Las Vegas at a lower cost. There's so much speculation that has been done on this issue, and no definite set price, only varying estimates. Some see the glamor of high speed trains as an indicator of price. To really know, we would have to test it out to see how much it would cost. In Europe and Asia, many take advantage of their high speed trains. In Spain, it was even affordable on an immersion trip budget.
With all this talk of money, it would seem that a high speed train gives nothing back. In fact, it really does.