Such a super express might become a reality in the coming years.  This project is just one of many which could get funding from the $!4.4 billion dollar rail investment package that passed the House Of Representatives on Wednesday. The New York Sun has more:
A two-hour rocket train between New York and Washington is a [...]

Earlier this month, Newsday had a piece about The Long Island Rail Road preparing for a possible Amtrak strike. Unfortunately at this time the strike is still a strong possibility. Anyhow here is the article courtesy of Newsday:
The Long Island Rail Road is working on contingency plans in case of a strike by Amtrak [...]