Dulles, Virginia Postal Service to allow Sterling businesses and residents to use Dulles as an alternative address. The USPS defines Dulles as an "acceptable" city name for the 20166 zip code, whose "actual" city name is Sterling. The addresses for shipping parcels to United States embassies and consulates, as well as their employees worldwide, are located in Dulles. The USPS city name for zipcode 20189 is Dulles. Washington Dulles International Airport is located partially in Dulles (although its postal address uses the Sterling name instead) and partially in Fairfax County. The community derives its name from the airport; the airport in turn
Washington Dulles International Airport mezzanine with more room for lines. A new train system, dubbed AeroTrain and developed by Mitsubishi, began in 2010 to transport passengers between the concourses and the main terminal. The system, which uses rubber tires and travels along a fixed underground guideway, is similar to the people mover systems at Singapore Changi Airport, Hartsfield–Jackson Atlanta International Airport, and Denver International Airport. The train is intended to replace the mobile lounges, which many passengers found crowded and inconvenient. The initial phase includes the main terminal station, a permanent Concourse A station, a permanent Concourse B station, a permanent midfield concourse station