Hall disc signals – sometimes referred to as "banjo signals" – generally fell out of use in the late Twenties and early Thirties as improved color light and searchlight signals came into use. The Reading Railroad was one of the last railroads to use these archaic signals; this rare color photograph was taken in 1947 near Reading, PA. As with lower-quadrant semaphores, disc signals displayed two aspects per unit: the home signal above, and the distant signal below. This signal is displaying its most restrictive indication with a red over yellow.