Exterior view showing the third, and current, Chicago Union Station shortly after it was completed in 1925. At the time, it served four railroads: the Pennsylvania, Burlington, Chicago & Alton, and Milwaukee. The architecture firm that designed the station was Graham, Anderson, Probst & White, which traces its lineage back to Daniel Burnham, the architect of Washington Union Station and the city planner of Chicago. Today, the structure is the national hub of Amtrak operations, and terminal for several Metra commuter lines. This photo appears on p. 52 of "More Classic Trains" by Arthur Dubin (Kalmbach 1974).