N.Y. Post Office Pneumatic Tube, c. 1912.
The first pneumatic tube mail system was installed in New York City in 1897. Each tube could carry between 400 and 600 letters that travel at 30-35 miles per hour. In its best days, the system was 27 miles long and connected 23 post offices, and included tubes over the Brooklyn Bridge to connect the General Post Office in Brooklyn to Church Street in Manhattan. Pneumatic tubes were used in New York by the US Postal Services until 1953.