The term METROLINER SUCCESSOR is referring to the Acela, a high-speed train operated by Amtrak in the Northeast Corridor of the United States. The Acela was introduced in 2000 as a replacement for the Metroliner service, which had been in operation since 1969. The Acela is capable of reaching speeds of up to 150 mph and has become a popular mode of transportation for commuters and travelers alike.