| 1 | FSR | The Flightstar Corporation | Callsign: Flightstar, | USA | AVCODES |
| 2 | FSR | Air Link Charters | Callsign: Flight Star, | CDN | AVCODES |
| 3 | FSR | Flightstar Corporation | | | ICAO1 |
| 4 | FSR | Fort Smith R.R. Co. | added 1/1992; 1/1994-7/2000; eliminated 10/2001; added 4/2002; 7/2005 | | NAKINA |
| 5 | FSR | Fort Smith R.R. Co. | added 1/92; 1/94-7/2000 | | NRHS |
| 6 | FSR | FORT SMITH RAILROAD CO. | | | PWRC |
| 7 | FSR | Fort Smith Railroad | | | RSRV |
| 8 | FSR | FORT SMITH RAILROAD CO | | | SCAC4 |
| 9 | FSR | ScotRail Railways Ltd. | Real: SR, 1999: 3016km standard gauge, electrified at 25kV 50Hz First ScotRail is the brand under which First Group PLC runs its railway franchise to operate all domestic passenger services within Scotland, as well as the cross-border Caledonian Sleeper service to London, England. First Group has its headquarters in Aberdeen, Scotland. On 17 October 2004 the franchise was transferred to First Group from National Express resulting in the rebranding from ScotRail to First ScotRail. This was the first time the franchise has been renegotiated since the privatisation of British Rail. | GB | TRAFFIC |
| 10 | FSRB | FOUR SEASONS RADIATOR | | | SCAC4 |
| 11 | FSRC | FOUR STAR CONSTRUCTION INC | | | SCAC3 |
| 12 | FSRC | FSR TRUCKING INC | | | SCAC4 |
| 13 | FSRF | FOSTER FUELS INC | | | SCAC4 |
| 14 | FSRH | FULCHER, SCOTT TRUCKING | | | SCAC4 |
| 15 | FSRM | FIVE STAR TRUCKING INC (5 STAR TRUC | | | SCAC3 |
| 16 | FSRN | FASTRANS INC | | | SCAC3 |
| 17 | FSRO | FRASIER TRANSPORT CORP | | | SCAC4 |
| 18 | FSRP | FIVE STAR RACING PRODUCTS | | | SCAC4 |
| 19 | FSRQ | FAST TRANSFER INC | | | SCAC4 |
| 20 | FSRR | Ferrosur S.A. de C.V. | added 10/2003; 7/2005; eliminated 10/2007; added 4/2008 | | NAKINA |
| 21 | FSRR | Ferrocarril del Sureste, S.A. de C.V. | 7/2000; eliminated 10/2003 | | NAKINA |
| 22 | FSRR | Ferrocarril del Sureste, S.A. de C.V. | Jul-00 | | NRHS |
| 23 | FSRR | FERROSUR SA DE CV [FERROCARRIL DEL SURESTE, SA DE CV] | | | PWRC |
| 24 | FSRR | Ferrocarril del Sureste de CV | | | RSRV |
| 25 | FSRR | FERROSUR S A DE C V | | | SCAC4 |
| 26 | FSRR | Ferrocarril del Sureste, S.A. de C.V. | | MEX | TRAFFIC |
| 27 | FSRS | FSR TRANSPORT LLC | | | SCAC4 |
| 28 | FSRU | SPANISH MINISTRY OF DEFENCE-SPANISH AIRFORCE | | E | BIC |
| 29 | FSRW | FREITAS, ROGER WILLIAM | | | SCAC3 |
| 30 | FSRW | FIRST (1ST) RATE AUTO SHIPPING | | | SCAC4 |
| 31 | FSRX | F.S. Royster Guano Co. | 7/1935-7/1937 | | NAKINA |
| 32 | FSRX | Funding Systems Railcars Leasing, Inc. | added 4/1981; eliminated 7/1982 | | NAKINA |
| 33 | FSRX | Funding Systems Railcars Leasing, Inc. | added 4/81; eliminated 7/82 | | NRHS |
| 34 | FSRX | *F. S. ROYSTER GUANO CO. | | | PWRC |
| 35 | FSRX | *FUNDING SYSTEMS RAILCARS LEASING, INC. | | | PWRC |
| 36 | FSRY | FARRIS, RC & CO | | | SCAC4 |
