How Pneumatic Tubes Work

The Air-powered Internet

Plate taken from the "Illustrated London News," showing men using pneumatic tubes at the Central Telegraph Establishment of the General Post Office.
Plate taken from the "Illustrated London News," showing men using pneumatic tubes at the Central Telegraph Establishment of the General Post Office.

In the 1850s, Great Britain's General Post Office commissioned a study of Medhurst's concept, and in the 1860s, awarded a contract to engineer T.W. Rammel to build a pneumatic tube system to carry mail throughout London [sources: Library – UC Berkeley, Grace's Guide] By 1886, London's tube system stretched for 34 miles (54.7 kilometers) underneath the city and transmitted 32,000 messages a day. Letters hurtled along at a speed of up to 51 miles (82 kilometers) per hour—not as fast as what Medhurst had promised, but still speedier than a horse-drawn mail wagon [source: U.S. Congress].

By the turn of the 20th century, New York had a pneumatic tube system that sent canisters of letters and parcels zipping in a loop under Manhattan at 30 miles (48 kilometers) per hour. And Boston, Chicago, Philadelphia and St. Louis had similar systems [source: Library – UC Berkeley].

Pneumatic transport seemed so ingenious that some people proposed using it for other things besides mail. In 1867, an inventor named Alfred Beach built and briefly operated a 300-foot-long (91-meter-long) pneumatic tube subway under a section of Broadway in Manhattan, in hopes that air-powered trains would catch on [source: Massachusetts Institute of Technology]. In 1913, Waldemar Kaempffert, managing editor of the prestigious publication Scientific American, actually proposed the idea of cooking meals in central kitchens and shipping them via pneumatic tube to people's homes. "If a letter can be shot through pneumatic tube from New York to Brooklyn, why not a five-course dinner?" he opined.

Just as Edwardian-age folks were starting to really go crazy about this newfangled pneumatic technology, World War I quickly cooled their ardor. The U.S. Post Office suspended the use of pneumatic mail transport, saying that it used too much fuel to power the air compressors that they needed. After the war, the service eventually was restored, but only in New York and Boston.

Private companies that would have built new systems stopped putting in bids because of all the Congressional regulations and gradually, the existing systems' capacity was outstripped by the growing volume of mail. Instead, the Post Office put its money into mail trucks, which had the added advantages of transporting mail to locations far more distant than a pneumatic tube system could reach and transporting larger packages. In 1953, U.S. Postmaster General Arthur Summerfield canceled pneumatic tube mail for good, and ordered the systems dismantled [source: Cohen].