KitMetro

KitMetro is a test cell in the game files of Fallout 3.

Layout
It appears to be pieces of a Metro tunnel. It is extremely dark and impossible to navigate. The name would indicate that this was used for prefabs in building larger versions of the Metro tunnels.

Appearances
KitMetro appears in the game files of Fallout 3 but should not be considered canon due to it being a test cell.