Lines are grouped into historic operating divisions. As passenger service declined during the 1950's, many divisions were consolidated.
Wabash Subdivision (Griffith-Peru)
Miami Subdivision (Peru-Cincinnati)
Northern Subdivision (Russell KY-Columbus)
Columbus Subdivision (Columbus-Toledo)
Athens Subdivision (Columbus-Athens)
Chicago Subdivision (Porter-Grand Rapids)
Detroit Subdivision (Grand Rapids-Detroit)
La Crosse Subdivision (New Buffalo-Wellsboro-La Crosse)
Baldwin Subdivision/Traverse City Subdivision/Petoskey Subdivision
Saginaw Terminal Subdivision (Saginaw-Plymouth/Bay City/Midland)
Toledo Subdivision (Plymouth-Michigan State Line)
Toledo Subdivision (Ohio State Line-Toledo)
Ludington Subdivision (Midland-Ludington)
Manistee Subdivision (Walhalla-Manistee)