A network of tunnels for pneumatic mail-transport tubes once buzzed with activity under the block now occupied by Chicago’s John C. Kluczynski Federal Building, Post Office, and Plaza. The post office housed in the old Chicago Federal Building, which occupied this site from 1905 until developers tore it down in 1965, utilized the tubes for a short period at the beginning of the twentieth century.

Pneumatic tube technology was promising in the first and second decades of the twentieth century. Pressurized air pushed through eight-inch wide tunnels could carry tubes at speeds up to thirty miles per hour, much faster than other forms of local transport. Recognizing the potential for faster mail delivery, the Chicago Postal Pneumatic Tube Service Company built nineteen miles of tunnels to transport mail in pneumatic tubes between the city’s central post office, housed in the Chicago Federal Building at the time, smaller post offices, and railway stations.

Pneumatic tube enthusiasts hoped to one day connect every home in the nation to their respective post offices via the pneumatic tube tunnel system. In Chicago, city leaders reviewed proposals to expand the post office’s tube system, but President Wilson crushed their hopes before they could launch expansion projects. Pneumatic tubes, he said in 1918, were less efficient than automobiles for transporting U.S. mail. Without federal support, plans to expand the postal service's use of the tubes fell apart.

A handful of other businesses and ventures experimented with pneumatic tubes. Chicago’s City News Bureau used them to transport news copy internally and city planners in New York City even discussed the possibility of using a large-scale tube system for mass underground transit. But without broad support, the systems gradually fell out of use, though some banks, post offices, factories, hospitals, and other businesses still use the technology to transport objects and documents internally.

Credits and Sources:

Cohen, Robert. "The Pneumatic Mail Tubes: New York's Hidden Highway And Its Development." USPS, August, 1999. Accessed July 2016. https://about.usps.com/who-we-are/postal-history/pneumatic-tubes.pdf

Loerzel, Robert. "Chicago's Strange History with Pneumatic Tubes." Chicago Magazine, September 5, 2013. Accessed July 2016. http://www.chicagomag.com/Chicago-Magazine/The-312/September-2013/Pneumatic-Tubes/

Pogrebin, Robin. "Underground Mail Road; Modern Plans for All-but-Forgotten Delivery System." New York Times, May 7, 2001. Accessed July 2016.  http://www.nytimes.com/2001/05/07/nyregion/underground-mail-road-modern-plans-for-all-but-forgotten-delivery-system.html?pagewanted=all

Historic photographs: "Chicago Post Office" c. 1900, courtesy Library of Congress; "View of Federal Center in Chicago, Illinois"  courtesy U.S. General Services Administration.

Written by Hope Shannon, Loyola University Chicago