| Abbreviation | Definition |
|---|---|
| FRLU | Farrell Lines Incorporated |
| FRMU | United Hydroponics |
| FRP | Fullerton Railway Plaza |
| FRR | Falls Road Railroad |
| FRR | Falls Road Railroad Company Incorporated |
| FRRS | Feather River Rail Society |
| FRRX | Feather River Rail Society |
| FRSA | Federal Railroad Safety Act |
| FRSU | China Ocean Shipping |
| FRSU | China Ocean Shipping Company |
| FRTX | Farm-City Transport Incorporated |
| FRTX | Frit Transportation (Farm-City Transport) |
| FRV | Fox River Valley Railroad (Wisconsin Central) |
| FRVR | Fox Valley and Western |
| FRVR | Fox Valley and Western Limited |
| FSCX | Frank Mitacek Railway Service |
| FSFL | BNSF Railway |
| FSHX | GE Rail Services |
| FSHX | General Electric Railcar Services Corporation |
| FSIX | Freight Services Inc. |