| Abbreviation | Definition |
|---|---|
| PRPX | Pacific Railroad Preservation Association |
| PRQZ | Pre-Rule Quiet Zone |
| PRR | Consolidated Rail Corporation |
| PRR | Pennsylvania RailRoad |
| PRR | Pennsylvania Railroad (Norfolk Southern) |
| PRR | Pennsylvania RailRoad (now ConRail) |
| PRRX | Pennsylvania Railroad (Norfolk Southern) |
| PRSC | Progress Rail Services Corp |
| PRSL | Consolidated Rail Corporation |
| PRSL | Pennsylvania-Reading Seashore Lines (Norfolk Southern) |
| PRSX | Progress Rail Services Corporation |
| PRT | Parr Terminal Railroad |
| PRT | Pas Rail Transit |
| PRTD | Portland Traction |
| PRTD | Portland Traction Company |
| PRV | Pearl River Valley Railroad |
| PRV | Pearl River Valley Railroad Company |
| PRWX | Railway Entertainment Services Limited |
| PRXU | Praxair Helium |
| PRY | Pioneer Industrial Railway |