Costs for state of good repair, capacity enhancement, and 427 miles of HSR from Washington D.C. to Boston, MA is now 151 billion dollars. The updated NEC HSR report puts the actual HSR bit at 110 billion in 2011 USD. In year of expenditure dollars, I believe that's 200 and 145 billion dollars respectively.
In keeping with Amtrak's ambitions of making everything in America far more costly than the rest of the world, the plan includes $5.2 billion for high speed rolling stock, of which there would be a grand total of 58 train sets acquired (12 in 2020, 32 in 2025, 14 replacing the original 12 in 2040). At 90 million USD each, that's about three times the cost of buying and maintaining 20 ETR 610s for 17 years, or three times the purchase price of a brand new AGV.
In all honesty, Amtrak needs to be purged of everyone who signed off on this report and thought it a good idea. The greatest roadblock to decent passenger rail service in America, both in the NEC and elsewhere, is Amtrak itself.