1900-1906 - Michigan Traction Co. (Battle Creek-Kalamazoo)
1903-1906 - Jackson & Battle Creek Traction Co.
1903-1904 - Lansing St. Johns & St. Louis Railway Co.
1904-1906 - Lansing & Suburban Traction Co.
1905-1908 - Detroit Flint & Saginaw Railway Co. (Saginaw-Frankenmuth)
1908-1915 - Saginaw & Flint Railway
1906-1923 - Michigan United Railways Co.
1923-1929 - Michigan Electric Railway Co.
Interurban lines:
Jackson-Battle Creek (constructed 1903, discontinued 1928)
Battle Creek-Kalamazoo (constructed 1900, discontinued 1928)
Jackson-Lansing (constructed 1909, discontinued 1929)
Lansing-St. Johns (electrified 1904, discontinued 1929)
Lansing-Owosso (constructed 1911, discontinued 1929)
Saginaw-Frankenmuth (constructed 1905, discontinued 1927)
Saginaw-Flint (constructed 1909, discontinued 1929)
Replacement bus companies:
Southern Michigan Transportation Co. (1920's-1935)
Eastern Michigan Motorbuses (1935-1941)
Great Lakes Greyhound Lines (after 1941)
MICHIGAN RAILROAD CO.
1915-1919 - Michigan Railway Co.
1914-1919 - Saginaw Bay-City Railway Co.
1919-1928 - Michigan Railroad Co.
Interurban lines:
Saginaw-Bay City (constructed 1914, discontinued 1929)
Kalamazoo-Grand Rapids (constructed 1915, discontinued 1928)
Battle Creek-Allegan (electrified 1915, discontinued 1928)
Information on how the Michigan United Railway bus operations evolved into part of the Greyhound bus system.