Atomfall is filled with challenges, including numerous locked doors that require various keys and keycards to unlock. One such door is located at the Casterfell Dam, specifically within the Casterfell Data Dam Store, nestled in the Casterfell Woods. Here, you’ll encounter a secured entrance to the B 887126 Control Room, but locating the key is no easy task.
The key you seek belonged to an individual who unfortunately did not survive the calamity within the quarantine zone. To gain access to the control room, you will need to retrieve the key from their remains. However, typical of Atomfall’s design, this corpse is not situated conveniently. Read on to discover how to locate this elusive key.
Locating the B 887126 Control Room


To access the B 887126 Control Room, your first destination should be the Casterfell Dam Data Store. This location is critical, influencing potential outcomes related to characters Dr. Diane Garrow and Joyce Tanner, both of whom seek data from a terminal located within the Data Store. You can pinpoint this store on your map at coordinates 22.5 E, 92.4 N within the Casterfell Woods.
Upon arriving, you will find yourself in a dilapidated zone, where next to the Data Store entrance lies the B 887126 Control Room, currently out of reach. Now, the question remains: where is the key hidden?
Obtaining the B 887126 Control Room Key
Directly across from the Casterfell Dam Data Store, there is a toxic gas-filled tunnel. On the opposite side of this tunnel lies Bunker L9, which contains the Casterfell Woods Radio Tower Keycard. You can navigate through this tunnel from either the Data Store or the Bunker L9 entrances. However, ensure you bring sufficient Antidotes, as the gas will cause poison build-up. It is wise to consume an Antidote before entry, granting you temporary resistance against the poison.
If you choose to enter the tunnel from the Bunker L9 side, proceed with caution; Feral enemies roam the area, and you may encounter them again while retrieving the Casterfell Woods Radio Tower Keycard within Bunker L9.
Within the hazardous tunnel, you will find a body positioned near some shelves. Interact with this corpse to loot it, discovering a note entitled “The Proper Antidote”alongside the crucial B 887126 Control Room Key. With the key in hand, retrace your steps back to the control room.
Upon unlocking the door, you will have access to various loot items, including a B.A.R.D. Crate featuring a Training Stimulant. Additionally, you will see a console with a lever labeled Ventilation Override. Activating this lever will vent out the toxic gas in the tunnel, allowing you to subsequently return and gather any remaining items. This path also serves as a shortcut back to the Casterfell Dam Data Store, helping you avoid unnecessary encounters with druids along the way.