Lines are grouped into historic operating divisions. As passenger service declined during the 1950's, many divisions were consolidated.
Cleveland Union Terminal Line (Berea-Quaker)
Clark Branch (Cleveland Drawbridge-Clark)
Youngstown Line (Ashtabula-Youngstown)
Dayton Line (Columbus-Cincinnati)
Southern Branch (Columbus-Point Pleasant)
Zanesville Branch (Thurston-Zanesville)
Main Line (Elkhart-Indiana State Line)
Main Line (Ohio State Line-Toledo)
Chicago Line (Toledo-Cleveland)
Old Road (Elkhart-Adrian-Toledo)
Fort Wayne Branch (Fort Wayne-Jackson)
Dundee Branch (Dundee-Allegan)
Main Line (Chicago-Whiting)
Main Line (Whiting-Elkhart)
Chicago River & Indiana Railroad
Danville Branch (Chicago-Schneider-Danville)
Kankakee Branch (South Bend-Schneider)
Kankakee Branch (Schneider-Hennepin-Zearing)
Detroit Line (Detroit-Michigan State Line)
Detroit Line (Ohio State Line-Toledo)
Bay City Branch (Detroit-Bay City)
Michigan Line (Hammond-Porter)
Michigan Line (Porter-Kalamazoo)
Michigan Line (Kalamazoo-Detroit)
Joliet Branch (East Gary-Joliet)
Kalamazoo Branch (White Pigeon Jct.-Kalamazoo-Grand Rapids)
Saginaw Branch (Jackson-Lansing-Saginaw-Bay City-Midland)
Mackinaw Branch (Bay City-Gaylord-Mackinaw City)
Grand Rapids Branch (Jackson-Grand Rapids)
Air Line Branch (Jackson-Niles)