Its route bullet was colored blue on station signs, car rollsigns, and the official subway map since it ran on the IND Eighth Avenue Line.

AA service was restored as part of changes made in conjunction with the opening of the IND Sixth Avenue Line on December 15, 1940.

Rush hours, which at the time included Saturday mornings and afternoons, the AA did not run; it was replaced by the BB (later B) service, which instead ran on the Sixth Avenue Line.

[1][4] On May 6, 1985, as part of the elimination of double letters, the AA was renamed the K. This service operated between 168th Street and World Trade Center during midday, evenings, and weekends.

During rush hours, the C, formerly the CC, ran between Bedford Park Boulevard and Rockaway Park–Beach 116th Street, replacing the K as the local on Eighth Avenue.