In order to keep their Talon assassins rested and equipped while also needing to keep their actions clandestine remove any potential incriminating association with the assassin, the Court of Owls ensured that each Talon would have a satellite base secretly built within various buildings in Gotham City.
The bases are usually only active for as long as each Talon is active, whereas, after the Talon is decommissioned, the base is also decommissioned and when a new Talon is activated a new base is also sought.
In 1891, the Court of Owls established a nest in the abandoned 13th floor of the Old Wayne Tower.
The nest intended for Talon (Calvin Rose) was the Metropolitan Terminal, an abandoned train station on the edge of Gotham City which was originally built by the Court of Owls in the late 1800's to control those who would come to and leave the city. Targets would think themselves on the verge of freedom only to be snatched up through the ceilings of the train cars when they tried to leave. Within a few decades, Alan Wayne's Union Station would make the Metropolitan obsolete and it eventually closed its doors.