Acela is the name used by Amtrak for many of their trains in the northeastern part of the United States. It is often used to refer to only the high-speed trains which run between Washington and Boston via New York and Philadelphia, although these are more properly referred to as Acela Express as there also exist Acela Regional trains. Thanks to recent improvements to railroad infrastructure, the trains have become much faster; one can travel between Boston and New York in under four hours. This fact, combined with the convenience of the train as opposed to air travel after September 11, has led Amtrak to capture nearly half of the market share of travelers between Boston and New York City.

Acela Express trains are manufactured as a joint project between Bombardier (75%) and Alstom (25%). They reach a top speed of 160 mi/h (257.5 km/h) only on one 29 km (18 miles) stretch of track (High speed rail is usually defined as over 200 km/h, or about 125 mi/h). The average speed of the train in practice is below 110 mi/h (177 km/h).

Seats on the Acela Express are colored blue; the interior is largely white and brightly lit; there are tables in the first-class section, while other cars are business-class and include a car in which talking on cell phones is banned. The trains stop at the following stations (note: not all trains stop at all stations). Connections to local rail transit are indicated.