systems: January 2009 Archives

I'm in the midst of a bunch of intense writing on the origins of the pneumatic tube network. It's not done yet, but I'll share more here given the recent interest (thanks, Bruce, for the link!).

Introduced to combat the shortcomings of the telegraphic network in Paris, the subterranean Poste Pneumatique (Pneumatic Post) moved written telegraph messages from 1866 until 1984. The pneumatic tube network relieved the saturated telegraph network, delivering physical messages across the city and to the suburbs faster and more reliably than the telegraph. What first began as a one-kilometer line connecting Paris's stock exchange and central telegraph office opened to the public service in 1879, and by 1910 reached all arrondissements and nearby suburbs, contained 210 kilometers of underground tubes, and handled approximately nine million postal telegrams a year. By 1953 at its height, it was 450 km long--the largest in the world--processing more than 11 million pieces a year.

Why did it make sense to send a telegram via pneumatic tube? It was a set of factors related to urban conditions in the 19th century. Cities with high population, heavy commerce and finance and urban congestion made good candidates for pneumatic tube networks. Moreover, in Europe, the pneumatic tube mostly relieved a communication boom caused by inexpensive telegraphy and saturated telegraph networks. Devised as an auxiliary to the telegraph, a medium that could only transmit 40-50 messages of 20 words per hour in 1860, the pneumatic tube network addressed the issue of rapid, reliable communication within the city (though telegraphy still made sense for messages sent over longer distances).

Poste Pneumatique was under the operation of the telegraph office within the postal service, although it only moved physical, written cards and not electric messages. It offered Parisians a quick and reliable method of sending messages across their congested city--something that could not happen with overburdened telegraph lines or on urban streets. To send a "petit bleu," (the one on the right from this collection) as pneumatic messages were known, the sender composed a written message on a card and delivered it to a special Poste Pneumatique mailbox or the nearest post office. There, the postal telegraph desk delivered it via pneumatic tube receptacle to the addressee's closest post office, where a messenger (bicycle or later, motorcycle) would deliver it to the recipient--usually within two hours of its inscription.

By 1870, Paris also had an extensive network of vaulted sewers, built by Baron Haussmann during the Second Empire. The sewers were a natural conduit for other types of infrastructure (potable water, telegraph lines, and eventually electricity), making it easier to install pneumatic tube and compressed air lines and to access them in case of error.

Paris's pneumatic tube network was not the first--that was London, started in 1853) and by no means was it the only one. Urban tube systems existed all over the world, in Europe, North and South America, and Australia. London invented its pneumatic post in 1853. Berlin began its Rohrpost in 1865 and Vienna in 1878 Philadelphia followed suit for first class post in 1893 and New York in 1897. The technology transferred readily and with less competition than might have been expected (Austrian, German and French engineers shared technological improvements).

Urban tube networks existed for a surprisingly long time, remaining in operation until 1953 in New York, 1984 in Paris and 2002 in Prague (where it was only taken out of service by a flood that destroyed much of the tube infrastructure). They fell out of favor for different factors: in the US, the invention of the gasoline-powered truck in 1912 proved competitive; elsewhere, reliable telephone, and later fax service obviated the need for the networks. But still, telecommunication contends with issues of last mile delivery and economies of scale. And as interest in embedded computing grows, of objects imbued with interactivity, there's something extremely attractive about a physical system that shoots a physical message to its addressee.