They were briefly first operated by Penn Central Transportation (successor to the Pennsylvania Railroad, which originally ordered the equipment), then by Amtrak for 35 years.

[2][3][4] The first Acela Express trains ran in 2000, but due to equipment difficulties at the time they did not fully replace the Metroliners until 2006.

SEPTA refused its 11 Metroliners, intended for Philadelphia-Harrisburg service, in August; Penn Central eventually leased them, increasing its fleet to 61.

In October 1968, testing proved that the cars could operate the desired sub-3-hour trip time, and substation modifications by Westinghouse increased electrical reliability.

[8] Metroliner service finally started on January 16, 1969, with a single daily round trip leaving New York in the morning and Washington in the afternoon.

Penn Central added a computerized ticketing system in August 1969, and doubled service to six daily round trips on October 27.

[13] In 1982, Amtrak finished replacing the Budd Metroliner cars, which had developed problems with their motors limiting their speed, with trains powered by the Swedish-developed AEM-7 locomotives pulling Amfleet coaches.

As trainsets were repaired, the number of Metroliner trains declined to one round trip each weekday, which was finally discontinued on October 27, 2006.

Prior to the COVID-19 pandemic, Amtrak ran one non-stop Acela train each way on weekdays with a travel time of 2 hours and 33 (or 35 southbound) minutes,[15] comparable to the Metroliner service.

As of 2023, those trains have not been restored and the fastest travel time is now 2 hours 45 minutes with stops in Baltimore, Wilmington, Philadelphia, and Newark.

On October 31, 1982, Amtrak added two New England Metroliner round trips between New York City and Boston, which ran with diesel locomotives north of New Haven.