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- Pacific, Northern and Omineca Railway
- Parry Sound Colonization Railway
- Pembina Valley Railway
- Pembroke Southern Railway
- Peninsular Railroad
- Peninsular Railway
- Peninsular Railway - Illinois
- Peninsular Railway - Indiana
- Peninsular Railway - Michigan
- Peninsular Railway Extension Company
- Peterborough and Chemong Lake Railway
- Peterborough and Port Hope Railway
- Petitcodiac and Elgin Branch Railway
- Pleasant Bay Railway
- Polk and 49th Street Junction Railway
- Pontiac, Oxford and Northern Railroad
- Pontiac, Oxford and Port Austin Railroad
- Port Arthur, Duluth and Western Railway
- Port Dalhousie, St. Catharines and Thorold Electric Street Railway
- Port Dalhousie and Thorold Railway
- Port Dover and Lake Huron Railway
- Port Hope, Lindsay and Beaverton Railway
- Port Huron and Indiana Railway
- Port Huron and Lake Michigan Railroad
- Port Huron and Milwaukee Railway
- Port Huron Railroad Tunnel Company
- Port Whitby and Port Perry Railway
- Portage and North-Western Railway
- Portland Elevator Company
- Prescott County Railway
- Preston and Berlin Junction Railway
- Preston and Berlin Railway
- Prince Edward County Railway
- Prince Edward Island Car Ferry Terminals
- Prince Edward Island Ferry Service
- Prince Edward Island Railway
- Prince Charles
- Prince David
- Prince George
- Prince Henry
- Prince John
- Prince Robert
- Prince Rupert Dry Dock and Shipyard
- Prince Rupert Hotel Site
- Prince Rupert
- Prince William
- Public Markets
- Pullin and Copp
- Pullin, Virgil and Company's Express
Read more about this topic: List Of Canadian National Railways Companies