| Abbreviation | Definition |
|---|---|
| PBR | Patapsco and Back Rivers Railroad |
| PBRR | Pine Belt Southern Railroad Company |
| PBRR | Prairie Belt Railroad |
| PBSZ | CSX Intermodal |
| PBSZ | CSX Intermodal Incorporated |
| PBVR | Port Bienville Railroad |
| PC | Consolidated Rail Corporation |
| PC | Penn Central (Norfolk Southern) |
| PCA | Consolidated Rail Corporation |
| PCA | Penn Central (Norfolk Southern) |
| PCAX | Pioneer Chlor Alkali |
| PCAX | Pioneer Chlor Alkali Company Incorporated |
| PCB | Consolidated Rail Corporation |
| PCB | Penn Central (Norfolk Southern) |
| PCC | Palouse River and Coulee City Railroad |
| PCC | Palouse River and Coulee City Railroad Incorporated |
| PCCX | Peabody Coal |
| PCCX | Peabody Coal Company ( Captive Service) |
| PCEX | Petromax Chemical Exchange (GE Rail Services) |
| PCFX | Pacific Car and Foundry |