As her popularity increased, Smith became a headliner on the Theatre Owners Booking Association (T.O.B.A.) circuit and rose to become its top attraction in the 1920s. Working a heavy theater schedule during the winter and performing in tent shows the rest of the year, Smith became the highest-paid black entertainer of her day and began traveling in her own 72-foot-long railroad car. Columbia's publicity department nicknamed her "Queen of the Blues," but the national press soon upgraded her title to "Empress of the Blues." Smith's music stressed independence, fearlessness, and sexual freedom, implicitly arguing that working-class women did not have to alter their behavior to be worthy of respect.