| Abbreviation | Definition |
|---|---|
| BRRC | Borinstein Railroad |
| BRRC | Borinstein Railroad Company |
| BRRR | Buffalo Ridge Regional Railroad |
| BRRRA | Buffalo Ridge Regional Railroad Authority |
| BRRX | Brooklyn Resource Recovery |
| BRRX | Brooklyn Resource Recovery Incorporated |
| BRS | Brotherhood of Railroad Signalmen |
| BRSR | Blue Ridge Scenic Railway |
| BRT | Brotherhood Of Railroad Trainmen |
| BRT | Bus Rail Transit |
| BRW | Black River and Western |
| BRW | Black River and Western Corporation |
| BRZU | Container Express Corporation |
| BS | Birmingham Southern Railroad |
| BS | Birmingham Southern Railroad Company |
| BSBU | Bigsteel Box Corporation |
| BSCX | Bethlehem Steel Corporation |
| BSDA | BSDA Railroad |
| BSIU | Blue Sky Intermodal |
| BSIX | Bethlehem Steel Corporation |