All track diagrams are as current as possible, except for the "Classic Track Diagrams", which show certain railroads as they previously existed, prior to elimination of multiple tracks, downgrading, or occasionally abandonment.
Also included for most lines within 100 to 150 miles from Chicago, is historical information for former or lost passenger stations, including locations identified using Google Maps.
For most of these lines, historical information is included for interlocking towers. The lists of stations do not always include where abandoned railroads formerly crossed, and certain present railroads due to inconsistent employee timetable information. But the historic tower data generally provides more complete information on historic crossings.
Further explanations on the interlocking histories provided, is available through the below link. Providing more direct access to the interlocking tower histories.
Chicago Track Elevation
A chronological list of ordinances passed by the City of Chicago, requiring the main line railroads to elevate their trackage. Much of the trackage was elevated between the 1890's and the early 1900's, these elevation projects contributed to Chicago becoming a great railroad center.