Networks of pneumatic tubes speeded mail beneath city street beginning in the 1890s. Pneumatic carriers holding 600 letters traveled at about 35 miles per hour. The tubes were introduced in 1893 in Philadelphia, Boston, Brooklyn, New York City, Chicago, and St. Louis also adopted the system. Soon these cites had over 56 miles of tubes. Suspended in World War I as an economy measure, the service was restored in New York and Boston after the war. By the 1950s, increasing mail volume and changing urban landscapes made pneumatic tubes impractical. Post offices and businesses could move easily, but the underground pneumatic system could not.
Narrator: In 1893 the Philadelphia post office tried a radically different and speedy way to
transfer mail between post offices.
They installed a network of underground pneumatic tubes.
Cylinders like these carrying mail
were pushed or pulled through the tubes by compressed air or vacuum suction.
Cylinders flew through the tubes as fast as 35 miles per hour.
Other cities followed the example.
In New York City, a forty-minute male wagon route was covered by the tubes in seven minutes.