The Acela Express (/əˈsɛlə/ ə-SEL-ə; colloquially abbreviated to Acela) is Amtrak's flagship service along the Northeast Corridor (NEC) in the Northeast United States between Washington DC and Boston via 14 intermediate stops including Baltimore, Philadelphia, and New York City. The route contains segments of high-speed rail, and Acela Express trains are the fastest trainsets in the Americas; they attain 150 mph (240 km/h) on 28 miles (45 km) of the route.[8] Acela trains use tilting technology, which helps control lateral centrifugal forces, allowing the train to travel at higher speeds on the sharply curved NEC without disturbing passengers.[9]