| Abbreviation | Definition |
|---|---|
| PGHX | Trinity Rail Management |
| PGLZ | Prudential Grace Lines |
| PGMX | Procter and Gamble Manufacturing |
| PGR | Portable Guard Rail |
| PGR | Progressive Rail |
| PGRV | Pigeon River Railroad |
| PGRV | Pigeon River Railroad Company |
| PGRX | AmeriGas Propane |
| PGRX | AmeriGas Propane L. P. |
| PGTX | Trinity Rail Management |
| PGTX | Trinity Rail Management Incorporated |
| PHCR | Port Colborne Harbour Railway |
| PHD | Port Huron and Detroit Railroad (CSX Transportation) |
| PHD | Port Huron and Detroit Railroad Company |
| PHL | Pacific Harbor Line |
| PHL | Pacific Harbour Line Incorporated |
| PHLB | Port Hope, Lindsay, and Beaverton Railway |
| PHNX | General American Marks (GATX Corporation) |
| PHRU | Nigeria National Petroleum Corporation |
| PI | Paducah and Illinois Railroad |