| 401 | OCE | RETIRED 06-05-92 (603) ATP [OREGON, CALIFORNIA & EASTERN RY.] | | | PWRC |
| 402 | OCE | Oregon, California and Eastern Railway | | | RSRV |
| 403 | OCEA | OCEANBULK LINE | | | SCAC3 |
| 404 | OCEANC | Ocean County Department of Transportation Services | City: Toms River, NJ | US-NJ | TRAFFIC |
| 405 | OCEB | OCEAN BEACH TRANSFER & STORAGE, INC | | | SCAC3 |
| 406 | OCEC | OCEAN CITY EXPRESS CO INC | | | SCAC4 |
| 407 | OCEE | OCOEE RIVER TRANSPORT INC | | | SCAC4 |
| 408 | OCEL | OCEAN EXPRESS LINE INC | | | SCAC3 |
| 409 | OCEL | ODIS CRANE & EQUIPMENT LLC | | | SCAC4 |
| 410 | OCEN | OCEAN SPRINGS TRANSFER & STORAGE IN | | | SCAC3 |
| 411 | OCEN | OCEAN SPRINGS TRANSFER & STORAGE IN | | | SCAC4 |
| 412 | OCEO | OCEANO SHIPPING CO INC | | | SCAC4 |
| 413 | OCEQ | OCEAN TRANSPORT | | | SCAC4 |
| 414 | OCET | OCEAN TERMINALS, INC | | | SCAC3 |
| 415 | OCET | OCEAN TERMINALS INC | | | SCAC4 |
| 416 | OCEU | OCEAN EXPRESS COMPANY | | ET | BIC |
| 417 | OCEU | OCEAN EXPRSS COMPANY | | | SCAC4 |
| 418 | OCEX | OREGON COASTLINE EXPRESS | | | PWRC |
| 419 | OCF | Ocean Airlines | Callsign: Explorer, Ceased operations. | F | AVCODES |
| 420 | OCFA | SNCF: Office des Chemins de fer Algériens | | DZ | TRAFFIC |
| 421 | OCFC | O C F CONSOLIDATION SVCS INC | | | SCAC3 |
| 422 | OCFG | OWENS CORNING FIBERGLAS CONSTR SVCS | | | SCAC3 |
| 423 | OCFI | OCEAN FREIGHT HANDLERS INC | | | SCAC3 |
| 424 | OCFI | OCEAN FREIGHT HANDLERS INC | | | SCAC4 |
| 425 | OCFP | O.C.F. / PRO RACING FUELS | | | SCAC4 |
| 426 | OCFR | OCEAN FRESH TRADING CO | | | SCAC4 |
| 427 | OCFS | OTTAWA COUNTY FARM SUPPLY | | | SCAC3 |
| 428 | OCFX | Owens Corning Fiberglas | 1/1994-7/2005 (not listed) | | NAKINA |
| 429 | OCFX | Owens Corning Fiberglas | 1/94-7/2000 | | NRHS |
| 430 | OCFX | *(CSXT) RETIRED 06-24-93 ATP | | | PWRC |
| 431 | OCFX | +OWENS CORNING FIBERGLAS | | | PWRC |
| 432 | OCFX | Owens Corning Fiberglass | | | RSRV |
| 433 | OCG | Oceanogate Italia srl | | I | TRAFFIC |
| 434 | OCG | Oceanogate Italia SPA | | IT | VKM |
| 435 | OCGC | OCEAN CARGO CARRIERS INC | | | SCAC4 |
| 436 | OCGL | OCEAN CRUISE GUIDES | | | SCAC4 |
| 437 | OCGM | OLDCASTLE GLASS-MONTREAL | | | SCAC4 |
| 438 | OCGR | ORCA CREATIVE GROUP INC | | | SCAC4 |
| 439 | OCGT | O'CONNOR, GEORGE TRUCKING | | | SCAC4 |
| 440 | OCGU | TEXTAINER EQUIPMENT MANAGEMENT LIMITED | | USA | BIC |
| 441 | OCGX | Ohio Cities Gas Co. (The Pure Oil Co.) | 8/1920 | | NAKINA |
| 442 | OCGX | PURE OIL CO. [OHIO CITIES GAS CO.] | | | PWRC |
| 443 | OCHE | OCHOA COMERCIAL | | | SCAC4 |
| 444 | OCHF | OCHOCO FEED TRUCKING | | | SCAC4 |
| 445 | OCHK | ORCHID TRUCKING | | | SCAC4 |
| 446 | OCHL | OLLISON COACH LINE INC | | | SCAC3 |
| 447 | OCHM | OLSONS CUSTOM HAULING | | | SCAC4 |
| 448 | OCHN | OCEAN CARGO HANDLING SERVICES INC. | | | SCAC3 |
| 449 | OCHO | OCHOA CAMPOS, ANTONIO | | | SCAC4 |
| 450 | OCHP | OCEAN HILL TRANSPORT INC | | | SCAC4 |
| 451 | OCHS | OCHS OIL COMPANY | | | SCAC4 |
| 452 | OCHT | OUACHITA TRUCKING CO | | | SCAC3 |
| 453 | OCHT | OCHOA TRUCKING | | | SCAC4 |
| 454 | OCHZ | OIL CITY HISTORICAL SOCIETY | | | PWRC |
| 455 | OCIC | OLSEN CONTROLS INC | | | SCAC3 |
| 456 | OCID | OCEANSIDE SHIPPING, ATHENS, GREECE | | | SCAC4 |
| 457 | OCIDA | ONEIDA COUNTY INDUSTRIAL DEVELOPMENT AGENCY | | | PWRC |
| 458 | OCIL | OSOWSKI & CO INTERNATIONAL LTD | | | SCAC3 |
| 459 | OCIL | OCEANA INTERNATIONAL | | | SCAC4 |
| 460 | OCIN | OCEANS INTERNATIONAL CORPORATION | | | SCAC3 |
| 461 | OCIN | OCEANS INTERNATIONAL CORPORATION | | | SCAC4 |
| 462 | OCIO | OLDENDORFF CARRIERS (INDOTRANS) | | | SCAC3 |
| 463 | OCIO | OLDENDORF CARRIERS | | | SCAC4 |
| 464 | OCIP | OCEAN CONTAINER INC | | | SCAC3 |
| 465 | OCIP | OCEAN CONTAINER INC | | | SCAC4 |
| 466 | OCIQ | OFFICEMAX INCORPORATED | | | SCAC4 |
| 467 | OCIT | OCEANEERING INTERNATIONAL INC | | | SCAC4 |
| 468 | OCIU | ARKEMA INC. | | USA | BIC |
| 469 | OCIU | Arkema | | | RSRV |
| 470 | OCIU | ATOFINA CHEMICALS INC | | | SCAC4 |
| 471 | OCIV | OCEANS CONSOLIDATORS INC | | | SCAC4 |
| 472 | OCIZ | ONEIDA COUNTY INDUSTRIAL DEVELOPMENT AGENCY | | | PWRC |
| 473 | OCJ | OverStar S.r.l. d/b/a Over Star Jets | Callsign: Overstar, | RSM | AVCODES |
| 474 | OCJ | OKLAHOMA CITY JUNCTION RAILWAY CO. | | | PWRC |
| 475 | ÖCJ | Östra Centralbanan | 1902 - 1937 | S | svenska-lok.se |
| 476 | OCJB | OCEAN STATE JOBBERS INC | | | SCAC4 |
| 477 | OCJJ | OROZCO CONTRERAS, JUAN JAIME | | | SCAC4 |
| 478 | OCK | Otto Conrad Eisenbahnbau und Tiefbauges. mbH & Co. | | DE | VKM |
| 479 | OCKP | ON DECK TRANSPORTATION INC | | | SCAC4 |
| 480 | OCKS | OCEAN KING SHIPPING CORPORATION | | | SCAC3 |
| 481 | OCKS | OCEAN KING SHIPPING CORPORATION | | | SCAC4 |
| 482 | OCL | Over-night Cargo Limited | Callsign: Overnight, | WAN | AVCODES |
| 483 | OCL | OCL (Barbados) Ltd. | Callsign: Soca, | BDS | AVCODES |
| 484 | OCL | OTTUMWA CONNECTING LINE | | | PWRC |
| 485 | OCLA | ONE CLOTHING | | | SCAC4 |
| 486 | OCLC | ONE CALL LOGISTICS AND TRANSPORTATI | | | SCAC4 |
| 487 | OCLD | OCEANIC LIMITED INC | | | SCAC3 |
| 488 | OCLD | OMIMEX CANADA LTD | | | SCAC4 |
| 489 | OCLE | OLYMPIC LINE EXPRESS | | | SCAC3 |
| 490 | OCLE | OCEAN LINK INC | | | SCAC4 |
| 491 | OCLG | OLDCASTLE LAWN & GARDEN INC | | | SCAC4 |
| 492 | OCLH | OSBORNE, CARL L HELICOPTER TRANSPOR | | | SCAC4 |
| 493 | OCLI | OCEAN CONCO LINE INC | | | SCAC3 |
| 494 | OCLI | OCEAN LOGISTICS CORP | | | SCAC4 |
| 495 | OCLK | OCEANLINK SHIPPING LTD. | | | SCAC3 |
| 496 | OCLK | OCEANLINK SHIPPING LTD. | | | SCAC4 |
| 497 | OCLL | OWNERS COURIERS LLC | | | SCAC4 |
| 498 | OCLN | OCEANIC CONTAINER LINE INC | | | SCAC4 |
| 499 | OCLP | ONE CALL LOGISTICS SUPPORT LLC | | | SCAC4 |
| 500 | OCLQ | ONE CALL LOGISTICS SOLUTIONS INC | | | SCAC4 |
