The Acela is Amtrak's flagship passenger train service along the Northeast Corridor (NEC) in the Northeastern United States between Washington, D.C., and Boston via 13 intermediate stops, including Baltimore, New York City and Philadelphia. Acela trains are the fastest in the Americas, reaching 150 miles per hour (240 km/h), but only over 49.9 miles (80.3 km) of the 457-mile (735 km) route.

Washington Union Station, known locally as Union Station, is a major train station, transportation hub, and leisure destination in Washington, D.C. Designed by Daniel Burnham and opened in 1907, it is Amtrak's headquarters, the railroad's second-busiest station, and North America's 10th-busiest railroad station. The station is the southern terminus of the Northeast Corridor, an electrified rail line extending north through major cities including Baltimore, Philadelphia, New York City, and Boston, and the busiest passenger rail line in the nation. In 2015, it served just under five million passengers.