The $8 billion in stimulus cash awarded to 13 high-speed rail corridors across the country may seem like a windfall, but there's a catch. The money isn't enough to finish any of the major projects.

State coffers are dry and federal spending is being cut back. So, it's unclear who will pay the rest of the multi-billion dollar bill.

Many states have been vague about how they would foot their part of the bill. But experts say most are counting on the federal government to cover at least half of their costs.

The proposed price tag of the high-speed rail corridors is estimated to cost at least $60 billion, and possibly more than $100 billion over the next decade or two. President Barack Obama announced the $8 billion in stimulus funds last week.