(Albany, NY)  --  State officials are hoping for a hefty federal loan to help with the construction of a new Tappan Zee Bridge.  State Transportation Commissioner Joan McDonald says the state has applied for a three billion dollar federal loan to help pay construction costs for the bridge, and she says federal transportation officials are reviewing the request.  Replacing the 56-year-old Tappan Zee Bridge has become a top priority for Governor Cuomo.  The cost is expected to begin at 5.2 billion dollars, and could rising to some 16 billion dollars if mass transportation projects get added on.  The Tappan Zee Bridge currently carries some 138,000 vehicles a day between Rockland and Westchester counties.