| Abbreviation | Railroad Name |
| PO | P&o
|
| PABST | Pabst Beer
|
| PCF | Pacific Car & Foundry
|
| PACC | Pacific Coast
|
| PE | Pacific Electric
|
| PFE | Pacific Fruit Express
|
| PGE | Pacific Great Eastern (BC Rail)
|
| PH | Pacific Harbor
|
| PHL | Pacific Harbor line |
| PIE | Pacific Intermountain Express
|
| PL | Pacific Lumber
|
| PDIL | Paducah & Illinois
|
| UNLTRD | Painted No Letters
|
| PAO | Pan Am Oils |
| PCRC | Panama Canal Railway
|
| PCL | Pardee Curtin Lumber
|
| PMP | Paris & Mount Pleasant
|
| PBR | Patapsco & Black River
|
| PEABODY | Peabody Coal
|
| PVS | Pecos Valley Southern
|
| PENINSULA | Peninsula Term
|
| PC | Penn Central
|
| PRRA | Pennsylvania & Atlantic
|
| PRS | Pennsylvania Readins & Seshore
|
| PRR | Pennsylvania RR
|
| PENNZOIL | Pennzoil
|
| PAE | Peoria & Eastern (*Conrail)
|
| PPU | Peoria & Pekin Union Railway
|
| PM | Peremarket (C&O/CSX)
|
| PFAULDER | Pfaulder
|
| PHRDG | Phadelphia & Reading
|
| PRT | Phadelphia Rapid Transit |
| PTC | Phil Brans Co |
| PBNE | Phil. Bethlehem&New England
|
| PHILTC | Philadelphia Transportation Co. |
| PHI | Phillips |
| PICKENS | Pickens
|
| PICKERING | Pickering Lumber Shays
|
| PN | Piedmont & Northern
|
| PILLSBURY | Pillsbury
|
| PIONEER Z | Pioneer Zephyr
|
| PITCH PINE | Pitch Pine & Prop
|
| PLE | Pittsburgh & Lake Erie
|
| PSM | Pittsburgh & Shawmut
|
| PWV | Pittsburgh & West Virginia
|
| PBCO | Pittsburgh Brewing Co.
|
| PITTS EL | Pittsburgh EL
|
| PIR | Pittsburgh Industrial RR
|
| PMY | Pittsburgh, McKeesport & Youghiogheny
|
| PSN | Pittsburgh, Shawmut & Northern
|
| POCLMB | Pocahontas Lumber Co.
|
| PCHNTS | Pochontas Lumber
|
| PCN | Point Comfort & Northern
|
| POLLOCK | Pollock Hot Metal Cars
|
| PAW | Port Angeles Western
|
| PHDR | Port Huron & Detroit
|
| PORT TOWNS | Port Townsend
|
| PORTLAND R | Portland Railway
|
| PTM | Portland Terminal
|
| PPLX | PPLX
|
| PPX | PPX
|
| PRATTSBURG | Prattsburgh
|
| PREF | Prefeered
|
| PCTN | Prescott & Northwestern
|
| PRESTON | Preston
|
| PRIV | Private Road
|
| PRWR | Providence & Worcester
|
| ALPX | Province Of Alberta Equipment
|
| PROX | PROX
|
| PSCX | PSCX
|
| PSCC | Public Service Co Of Colorado
|
| PULLMAN | Pullman Company
|
