The Northeast Express Train is a high-speed rail service operated by Amtrak that runs between Washington, D.C. and Boston, Massachusetts. The train is also known as the Acela, which is an acronym for 'Accelerated Corridor Express'. The Acela is the fastest train in the United States, with speeds of up to 150 miles per hour. It offers passengers a comfortable and convenient way to travel between the two cities, with stops in major cities along the way.