Proposed Mail Handling Chicago Tunnel System

Efforts to improve the efficiency of Chicago’s Tunnel System near the end of it’s working life.

This intriguing cutaway diagram/blueprint presents proposed improvements to Chicago’s subterranean system of tunnels that served businesses throughout the Central Business District (or Loop). It shows a new system of mail delivery in which a monorail would be used to transfer outgoing mail (already created) directly onto a waiting railcar. A pneumatic mail delivery system was already in place for smaller parcels and letters.

The Chicago Tunnel System, begun in the 1890s and largely completed by 1906, was a vast network of narrow freight tunnels running beneath downtown Chicago, designed to deliver coal, remove ashes, and transport mail and merchandise to buildings without clogging surface streets. Operated by the Illinois Tunnel Company, the system eventually spanned more than 60 miles of tunnels beneath the Loop, linking major department stores, post offices, and railroad stations until its abandonment in the late 1950s (not long after the blueprint was drafted).