DeKalb Avenue is the New York City Subway station associated with the system’s remaining full-time staffed control tower.
The Brooklyn station serves the BMT Fourth Avenue Line and the BMT Brighton Line, with B, Q, and R service nearby in the DeKalb Avenue complex. Its interlocking is unusually important because several routes converge, diverge, and bypass the station through complex trackwork.
The tower controls train movements through this busy Brooklyn junction. Subway control towers historically used mechanical or electro-mechanical equipment to manage signals and switches before centralized modern systems became common.
City Hall is famous for its surviving historic station architecture, including a preserved control tower, but that is a different distinction. DeKalb Avenue is the answer when the question concerns the operating, staffed tower associated with a major active interlocking.