Presidential Metro

The  is a network of metro tunnels that is added to Fallout 3 in the Broken Steel add-on.

It connects the Presidential Sub Level beneath the White House with Adams Air Force Base and The Capitol Building's East Wing. Protected and maintained by a computer system called M.A.R.Go.T., the area is guarded by Sentry Bots and swarming with ghouls.

Unmarked quest: Fatal Attraction
A holo-tape titled "Sorry, My Darling" is located up a flight of stairs on a bench near the exit to the capital building east wing. Finding and listening to it will start the unmarked quest Fatal Attraction.

Notable loot

 * Scoped .44 Magnum.
 * A number of Sensor Modules and Cameras.
 * Various different types of ammo.

Trivia

 * Like other real-life facilities built to serve as safehouses or escape routes for prominent government members, such as the Greenbrier resort, this secret metro system was likely constructed to quickly evacuate the President and his staff to the more secure location of Adams Air Force Base in the event of nuclear war. From the appearance of the White House terminal, however, the Line has not been in use at least since the Great War, and may never have fulfilled its original purpose.

Appearances
The appears in the Fallout 3 add-on Broken Steel.