Since 1962, one of the unique features of Dulles International Airport (IAD) has been the strange-looking “mobile lounges” used to shuttle passengers between the Main Terminal and other parts of the airport.
Sometime in 2009, passengers will begin traveling between the Main Terminal and the A, B, and C gates via an underground AeroTrain system. (The mobile lounges will continue to be used, for a while, for International arrivals and for reaching the D gates.)
You can read about the new train system here (in the Washington Post) and get a sneak preview of the new cars next time you visit the airport. There’s a full-size AeroTrain car on display in the Main Terminal (baggage claim level, by carousel #3) along with a video showing “the future of passenger travel at Dulles” and an exhibit about the airport’s past.