| Abbreviation | Definition |
|---|---|
| FSIX | Freight Services Incorporated |
| FSNU | Firestone Natural Rubber |
| FSR | Fort Smith Railroad |
| FSR | Fort Smith Railroad Company |
| FSRR | Ferrocarril del Sureste de CV |
| FST | Ferrocarriles Nacionales de Mexico |
| FSTU | Fastrac Intermodal |
| FSTU | Fastrac Intermodal L.L.C. |
| FSTX | Fuel Supply Trust |
| FSTZ | Fastrac Intermodal |
| FSTZ | Fastrac Intermodal L.L.C. |
| FSUD | Fort Street Union Depot |
| FSUD | Fort Street Union Depot Company |
| FSVB | Fort Smith and Van Buren Railway |
| FSVB | Fort Smith and Van Buren Railway Company |
| FTCU | Firsttank Corporation |
| FTCX | Far Port Cooperative |
| FTIU | FIBA Technologies |
| FTIX | FTIX Associates |
| FTL | Fort Lauderdale Station (Tri-Rail - AMTK) |