The opening of the subway was so incredible in the first decade of the 20th century, the new stations were frequently the subject of penny postcards, like this one, with its above ground and inside view.
“New York City’s subway system is the most complex of any in the world,” the back of the card reads. “The Brooklyn Bridge Station is the busiest in the world. It is estimated that 2,000,000 pass here daily.”
“The subway consists of four tracks, two for express trains and two for local. During the rush hours the trains run on a minute schedule.”
Ephemeral New York 