Acela Express
There are several high-speed rail services in the United States, notably the Acela Express, but all are limited to the Northeast Corridor. Amtrak uses the Acela Express them on a high-speed service between Washington, D.C. and Boston via New York City and Philadelphia along the Northeast Corridor (NEC) in the Northeast United States. The tilting design allows the train to travel at higher speeds on the sharply curved NEC without disturbing passengers, by lowering lateral forces. The Northeast Regional goes along the same route, but with more stops. All other high-speed rail services share part of the route.