The plan also proposes 3 million square feet in commercial, retail and residential development at the site just north of the US Capitol.
“This plan will transform the station into a world-class transportation hub to serve the region and the mobility needs of generations of passengers yet to come,” Amtrak President and Chief Executive Joe Boardman said in the statement.
According to the plan, six new high-speed tracks would be built at Union Station that would help commuters to reach Washington from New York City, and vice versa, about half-hour earlier, Reuters reported.
Amtrak gave no details about how the cost of $6.5 billion to $7.5 billion would be paid for.
President Barack Obama this month signed into law $105 billion in transportation spending over 27 months. Revenues have fallen from the main transportation funding source, the federal gasoline tax, as the economy has cooled and gas prices have risen.