| Abbreviation | Definition |
|---|---|
| FP | Fordyce and Princeton Railroad Company |
| FPAX | Formosa Plastics Corporation (Formosa Transrail Corporation) |
| FPAX | Formosa Transrail Corporation |
| FPBX | Federal Paper Board (International Paper Corporation) |
| FPBX | FPB Leasing Corporation |
| FPCX | Firestone Plastics Co. (Occidental Chemical Corporation) |
| FPCX | Occidental Chemical Corporation |
| FPFX | NorRail Incorporated |
| FPN | Ferrocarriles Nacionales de Mexico |
| FPPX | Fayette Power Project |
| FPXZ | Flexi-Van Leasing |
| FRA | Framingham Station (MBTA T Commuter Rail - AMTK) |
| FRA | Friends of Railway Administrators |
| FRB | Florida Rail Bird |
| FRCA | Freight Rail Customer Alliance |
| FRDN | Ferdinand Railroad (H and S Railroad) |
| FRDN | H and S Railroad Company Incorporated |
| FREU | ABS Industrial Verification |
| FREU | ABS Industrial Verification Incorporated |
| FRLU | Farrell Lines |