The $17.2 billion Hudson River tunnel project -- which received more than $11 billion in federal grants -- is repairing an existing tunnel, and building a new one for passenger railroad Amtrak and state commuter lines between New Jersey and Manhattan. Any failure of the current Hudson tunnel, which was heavily damaged during 2012's Superstorm Sandy, would hobble commuting in the metropolitan area that produces 10% of the country's economic output.