| 1 | SEC | South East College Of Air Training | Callsign: Secoat, | GB | AVCODES |
| 2 | SEC | 3D Aviation | | | ICAO1 |
| 3 | SECD | SEC SAWMILL EQUIPMENT COMPANY INC | | | SCAC4 |
| 4 | SECE | SEACOAST TRUCKING INC | | | SCAC4 |
| 5 | SECG | SILVER EAGLE CO | | | PWRC |
| 6 | SECG | SILVER EAGLE COMPANY | | | SCAC1 |
| 7 | SECG | SOUND FUEL LLC | | | SCAC4 |
| 8 | SECK | SECAS TRUCKING | | | SCAC4 |
| 9 | SECN | SEELEY AND ARNILL CONSTRUCTION | | | SCAC4 |
| 10 | SECO | SEWCO INC. | | | PWRC |
| 11 | SECO | SOUTHEAST COOPERATIVE SERVICE COMPA | | | SCAC4 |
| 12 | SECO | SECO Rail | | F | TRAFFIC |
| 13 | SECR | SCREAMIN EAGLE CARTAGE INC | | | SCAC4 |
| 14 | SECS | EUROTAINER S.A.R.L. | | | PWRC |
| 15 | SECS | EUROTAINER S.A.R.L | | | SCAC3 |
| 16 | SECT | SELECT TRANSPORTATION SERVICES DIVI | | | SCAC4 |
| 17 | SECU | EUROTAINER SA | | F | BIC |
| 18 | SECU | EUROTAINER SA | | | SCAC4 |
| 19 | SECV | SUPERIOR TRANSPORT INC | | | SCAC4 |
| 20 | SECX | Southern Extract Co. | 8/1920-4/1938 | | NAKINA |
| 21 | SECX | South-East Coal Co. | added 1/1975; 1/1975-1/1980; eliminated 7/1993; 1/1994 (not listed) | | NAKINA |
| 22 | SECX | General Electric Railcar Services Corp. | eliminated 1/2000 | | NAKINA |
| 23 | SECX | General Electric Rail Services Corp. | added 1/2000; 7/2000 (not listed); eliminated 10/2001 | | NAKINA |
| 24 | SECX | Southern Extract Co. (The Mead Corp.) | Apr-38 | | NRHS |
| 25 | SECX | South-East Coal Co. | added 1/75; 1/75-1/80; eliminated 7/93; 1/94 | | NRHS |
| 26 | SECX | General Electric Railcar Services Corp. | eliminated 1/2000 | | NRHS |
| 27 | SECX | General Electric Rail Services Corp. | added 1/2000; 7/2000 | | NRHS |
| 28 | SECX | *SOUTHERN EXTRACT CO. | | | PWRC |
| 29 | SECX | *(NATX) GENERAL ELECTRIC RAILCAR SERVICES CORP. [SOUTH EAST COAL CO.] | | | PWRC |
| 30 | SECX | South-East Coal | | | RSRV |
| 31 | SECX | South-East Coal Co. | | USA | TRAFFIC |
| 32 | SECY | STEWART TRUCKING | | | SCAC4 |
