 The most successful of Amtrak's routes, the Northeast Corridor, operates between Washington, D.C., and Boston, Massachusetts.The most popular and heavily used routes in the Amtrak system are those on the Northeast Corridor, which include the "Acela Express",and the "Northeast Regional".Amtrak's "Empire Service" trains provide frequent daily service along the 460-mile (740 km) Empire Corridor between New York City and Niagara Falls.