Chicago's Tunnels/the Chicago Pedway

I think I may be the last person on earth to hear about Chicago’s system of underground tunnels, but I find this really interesting! I’ve always known about the tunnel beneath Marshall Fields/Macy’s, but I didn’t realize that there was an extensive system of tunnels under Chicago.

In his 1992 New York Times article, “Chicago’s Well Kept Secret: Tunnels”, Don Terry describes a 250 million gallon flood of the tunnel system, caused by an underflow of the Chicago River. The construction of the tunnel system began in 1898, and finished in 1904. The tunnels run a total of 60 miles beneath the downtown area, and are about 40 feet bellow the city’s surface. The tunnels are 7.5 feet high and 6 feet wide; the walls are made of 10 inch thick concrete. The tunnels were initially built for telephone lines, but were more commonly used for small freight trains and coal transportations between buildings in the loop. Because they were so far underground, the tunnels were usually quite cool—about 55 degrees Fahrenheit, so the coal companies actually built shafts into movie theaters and sold the cool air to the theaters in the era before air-conditioning!

Two days before Terry’s report was released, a car-size hole developed in the concrete walls of one of the tunnels, approximately 15 feet beneath the bed of the Chicago River, causing massive flooding. The water rose up into the basements of some of the retail stores and office buildings that are connected by the tunnels.

The railroad tunnels described by Terry are separate from the Chicago Pedway, which is another series of underground tunnels designed to reduce traffic and protect pedestrians from bitter winter cold. According to Alice Maggio’s “Subterranean City: A Tour of Chicago’s Pedway”, there are two main parts of the Pedway: the first section connects twelve businesses and offices together in the Loop and also connects to the Metra and the CTA; the second section links part of east Michigan Avenue. The Marshall Field’s tunnel is in this section of the Pedway. The Pedway was constructed in 1951 when the city built tunnels to connect the Red Line and Blue Line stations at Jackson and Washington. Since then, the Pedway has been further developed, though it is inconsistent and not always interconnected. Maggio warns potential Pedway adventurers to expect confusion, as there are few maps within the Pedway itself.

I think I might have found myself a winter break adventure to embark upon!

Terry’s NYT article:
http://www.nytimes.com/1992/04/15/us/chicago-s-well-kept-secret-tunnels.html

Maggio’s Pedway Navigation Guide:
http://gapersblock.com/detour/subterranean_city_a_tour_of_chicagos_pedway_part_1/