Your photograph shows many classic Streamline Moderne elements:
Rounded corners that resemble the lines of a train or ocean liner.
Horizontal bands of windows emphasizing motion.
A tall vertical marquee (originally illuminated with the Greyhound name and logo).
Smooth blue enamel panels with contrasting white trim.
Symmetrical façade centered on the main entrance.
This style was widely used for Greyhound terminals because it projected a modern, efficient image for bus travel. Many of these stations were designed by architect William Strudwick Arrasmith, who created dozens of Greyhound terminals across the eastern United States in the 1930s and 1940s.
