Arlington Library
A building virtually untouched by the war. Occupied by Raiders, who are trapped within by Brotherhood of Steel paladins. Located opposite the Alexandria Arms, it serves as the location for several quests and also the place to pick up one of the six Sheet Music copies in the game for Agatha (the others are in Vault 92, Springvale School , the National Archives, the Statesman Hotel, and Roosevelt Academy). To complete the final stage of writing the "Wasteland Survival Handbook," the protagonist must speak with Scribe Yorling, who will then grant them access to download the card archive from the computer's memory.
To complete the quest, the hero must also locate the library's mainframe in the heart of the Raiders' position. To do this, Yorling will assign two Brotherhood paladins, who will begin patrolling the rooms along a specific route, clearing them with the protagonist's help. It is recommended to immediately go up to the second floor to be on the same level with the Raiders and be able to attack them from the flank.
Loot: 10 Pre-War Books, Inkwell (quest item for completing "Stolen Independence"), Sheet Music, Guns and Bullets, Big Science Book, Tumblers Today, Lies for Congressmen, Tales of a Junktown Trader, Quantum Cola, Invisibility Cloak, Dog Tags, Power Armor and weapons from fallen BS Paladins, Non-Radioactive Apple, and occasionally a Scoped .44 Magnum.
Arlington Sewers
A small location, unmarked on the Capital Wasteland map, southeast of Arlington Library. It consists of three levels and is used as a base by Raiders (six in total, respawning every 72 hours). The loot is minor (three Chinese assault rifles and a .44 Magnum with a scope in a safe). Near the entrance to the sewers, a sunken pleasure boat with a couple of gun zincs is moored by the riverbank.
Source: stopgame.ru, Orcidea
See also:
Canterbury Commons (and Superheroes),
Temple of Unity and the Republic of Dave,
Fallout 3: Herdershade and Rokopolis