Under the London Underground is a miniature railroad that moves mail from one part of the city to another. Less well known is a series of pneumatic tubes that moved mail beneath the streets of New York City from post office to post office before 1900.

Construction of the tubes began in 1897. By 1908, the pneumatic service was taken over by the New York Mail & Newspaper Transportation Company. The service continued until 1918, when the maintenance costs were thought to be impractical for the small volume of mail transported. When a post office moved, for example, the streets had to be dug up to reroute the tubes. And the pneumatic service saw competition from the automobile, which could deliver mail two to three times faster than a horse-drawn cart with equal or greater volume and more than 10 times the volume of a pneumatic tube.

Automobile and truck transportation signaled the end of the tube system, but in New York City it remained in operation until 1953. The owner of the pipes made several attempts to sell the defunct system, offering it to Con Edison and the United Parcel Service, with no success. Other tubes snaked under Boston, Philadelphia, Chicago, and St. Louis. In Manhattan, they extended about 27 miles, from the old Custom House in Battery Park to Harlem and back through Times Square, Grand Central Terminal and the main post office near Pennsylvania Station. At the City Hall station, the mail went over the brand new Brooklyn Bridge to the general post office in Brooklyn.