If someone were to say "The Chicago Tunnel System" many people mistakenly think of Chicago's subway system, not realizing there are a variety different tunnels beneath the city streets.
The different types of tunnel systems in Chicago are as followed
Chicago Subway Tunnels
Not named for the transit line color given by the CTA rather the streets they travel beneath. These include the state street subway and milwaukee-dearborn subway
Chicago Deep Tunnel
People in Chicago are generally aware of or have heard of this project, but few can recall images of what this project is like, despite that it's been well under construction for decades and incredibly expensive. Began in 1975, deep tunnel has a pricetag of $4 billion and will consist of over 100 miles of tunnel mostly 30+ feet in diameter. This project will mitigate pollution problems and improve water quality throughout the chicagoland area. Despite that the project has been on schedule and on budget, the project does have its critics claiming it's too expensive and there are better alternatives.
Photo source: http://www.debrashore.org/annualreport.html
Photo source: http://synergysalesassociates.com/images/cdc%20tunnel.jpgChicago Tunnel System
This is the system I'd like to focus on in this thread. Generally, the public is largely unaware of this system.....unfortunately, it could be said that this reason is what led to the The Chicago Flood in 1992.
The Chicago Tunnel System or Chicago Tunnel Company operated from 1906 to 1959. Nearly 60 miles of tunnel were constructed 40 feet below the loop and surrounding area. Smaller gauge locomotives and rail cars would move freight and mail throughout the city with stations in almost every major building at basement level.
An image of a typical grand union beneath a city intersection.
What one of those grand unions look like today.
Such a system was effective because Chicago's streets were crowded or else river traffic would cause bridge delays. Interestingly the first 16 miles of the system were constructed illegally without the city's knowledge. Dirt had to removed at headhouses disguised as legitimate businesses in order for construction work not to be detected.
Service to the basement level of a building
Today, the majority of the tunnel system is largely abandoned and unlit. Some of the old rail cars are still left down there but difficult to remove. A few portions of the system had been removed to accommodate the subway system while others have been converted to utility tunnel use. Initially, the system was somewhat accessible but few ventured down because of harsh conditions. As security concerns arose in recent years, all tunnels are heavily sealed off. The only portion I've personally ever been shown was a locked door in the S2 level sub-sub-basement of my office building by our security guard. No one, not even the management company of the building can get in because of a second lock owned by the city. Such a case is similar for most buildings downtown.
It's highly unlikely this system will ever go back into service. Despite being a very complex engineering project, Chicago in modern times still turns to more traditional methods of speedy mail and parcel delivery by using messengers...obviously a much cheaper alternative to running trains.
I urge you to check out this site which features photos taken by a former ComEd employee back in the 1980'shttp://users.ameritech.net/chicagotunnel/tunnel3.html
This site is the source of the few photos posted above.