| Abbreviation | Definition |
|---|---|
| PRY | Pioneer Industrial Railway Company |
| PRYL | Port Royal Railroad |
| PS | Pittsburg and Shawmut Railroad |
| PS | Pittsburg and Shawmut Railroad Company |
| PSAP | Puget Sound and Pacific Railroad |
| PSAP | Puget Sound and Pacific Railroad Company |
| PSAZ | Pacific Northwest Perishable Shippers Association |
| PSBU | Contship |
| PSCX | Public Service Company of Colorado |
| PSCX | Public Service of Colorado |
| PSFL | Puget Sound Freight Lines |
| PSFZ | Flexi-Van Leasing |
| PSHU | Ravenscroft Holdings |
| PSIX | PSI Energy |
| PSIX | PSI Energy Incorporated |
| PSL | Peabody Short Line (Canadian National Railways) |
| PSLL | Plymouth Short Line Limited |
| PSMT | Patiala State Monorail Trainways |
| PSNU | Pacific Steam Navigation |
| PSNU | Pacific Steam Navigation Company |