1908-1918 - Oregon Electric Railway Co.
1918-1933 - Oregon Electric Railroad Co.
Interurban lines:
Portland-Salem (1908-1933)
Portland-Forest Grove (1908-1932)
Portland-Woodburn (1909-1933)
Salem-Eugene (1912-1933)
Albany-Corvallis (1913-1931)
1893-1900 - East Side Railway Co.
1900-1902 - Portland City & Oregon Railway Co.
1902-1906 - Oregon Water Power & Railway Co.
1906-1924 - Portland Railway Light & Power Co.
1924-1930 - Portland Electric Power Co.
1930-1958 - Portland Traction Co.
Interurban lines:
Portland-Oregon City (1893-1958)
Portland-Gresham (1903-1958)
Gresham-Boring (1903-1935)
Boring-Cazedero (1903-1933)
Gresham-Troutdale (1909-1927)
Montavilla-Gresham (1911-1927)
Gresham-Bull Run (1911-1931)
1914-1929 - Southern Pacific Railroad
Interurban lines:
Portland-Hillsboro-Whiteson (1914-1929)
Portland-Oswego-Whiteson (1914-1929)
Whiteson-Corvallis (1917-1929)
Electric interurban service operated by a "steam" railroad.
Replacement bus companies:
Southern Pacific Motor Transportation Co. (1927-1931)
Oregon Motor Stages (1931-1953)
Pacific Greyhound Lines (after 1953)
1909-1923 - United Railways Co.
Interurban lines:
Portland-Wilkesboro (1909-1923)
1893-1930 - Willamette Falls Co.
Interurban lines:
West Linn-Willamette (1893-1930)
1915-1933 - Willamette Valley Southern Railway
Interurban lines:
Oregon City-Mount Angel (1915-1933)