An old Illinois Central-style color-light signal attached to a bridge on the St Charles Air Line just south of downtown Chicago. The line was built as a cross-town connector between the IC, CB&Q and C&NW, and is today jointly operated by Canadian National and BNSF (Amtrak trains that run on the former IC to the south use it too). I am standing on the abandoned Chicago & Western Indiana right of way below the bridge, that once led to Dearborn and Grand Central Stations.