Grand Trunk Western, long affiliated with CN prior to absorption into the system, has long used named subdivisions for its lines.
South Bend Subdivision (Munster-Battle Creek)
Flint Subdivision (Battle Creek-Port Huron)
Kalamazoo Service Track (Pavilion-Kalamazoo)
Mount Clemens Subdivision (West Detroit-Port Huron)
Holly Subdivision (east of Durand) and Grand Rapids Subdivision (west of Durand) evolved as follows:
Detroit-Milwaukee Jct. (Sold to Detroit Connecting Railroad)
Milwaukee Jct.-Durand (CN Holly Subdivision)
Durand-Owosso (Sold to Huron & Eastern Railway)
Owosso-Lowell (abandoned)
Lowell-Grand Rapids (Sold to Grand Rapids Eastern Railroad)
Grand Rapids-Coopersville (Sold to Coopersville & Marne Railway)
Coopersville-Grand Haven (abandoned)
Line Sold to Huron & Eastern Railway
Saginaw Subdivision (Durand-Saginaw-Bay City)
Line Sold to Great Lakes Central Railroad
Greenville Subdivision (Ashley-Middleton-Muskegon)
Abandoned Lines
Cass City Subdivision/Romeo Subdivision/Jackson Subdivision
Shore Line Subdivision (West Detroit-Toledo)
Flat Rock Subdivision (Detroit-Diann)
Dearborn Subdivision (DT&I Jct.-Rouge Yard)
Line Sold to Indiana & Ohio Railway
Flat Rock Subdivision (Diann-Delta OH)
Abandoned Lines