O
- Oakes, Thomas Fletcher (1843–1919), NP 1888-1893.
- Oeftering, Heinz Maria, DB 1957-1972.
- Ogden, William Butler (1805–1877), G&CU 1848-1862, UP 1862-1863.
- Ohmura, Takuichi, South Manchuria Railway 1939-1943.
- Olyphant, George Talbot, D&H 1858-1869.
- Olyphant, Robert M., D&H 1884-1903.
- Osborn, Prime F., III, SCL, CSX
- Osipów, Andrzej (born 1953), SKM 2006–present.
- Otsuka, Mutsutake, JR East -present.
Read more about this topic: List Of Railroad Executives