S
- Saguenay and Lake St. John Railway
- St. Boniface Western Land Company
- St. Catharines, Merritton and Thorold Street Railway, Company
- St. Catharines and Niagara Centre Railway
- St. Catharines Street Railway
- St. Charles and Huron River Railway
- St. Clair Frontier Tunnel Company
- St. Clair Tunnel Company
- Saint John and Quebec Railway Bridge Company
- Saint John and Quebec Railway
- Saint John and Quebec Railway Trust Company
- Saint John Valley Railway
- Saint John's Dry Dock
- Saint Joseph Valley Railway
- St. Lawrence and Atlantic Railroad
- St. Lawrence, Lower Laurentian and Saguenay Railway
- St. Lawrence and Ottawa Grand Junction Railroad
- St. Louis, Richibucto and Buctouche, Railway
- Saint Martin's Railway
- Saint Martin's and Upham Railway
- Saint Maurice Railway and Navigation Company
- Salisbury and Albert Railway
- Salisbury and Harvey Railway. Company
- Saratoga and St. Lawrence Railroad
- Saskatchewan and North Western Railway
- Saskatchewan Bridge Company
- Saskatchewan Midland Railway
- Saskatchewan North Western Railway
- Shawinigan Falls Terminal Railway
- Societe Immobiliere de la Rue Scribe
- South Chicago and Western Indiana Railroad
- South Norfolk Railway
- South Shore Railway
- Southern New England Railway
- Southern New England Railway
- Southern Vermont Railway
- Stanstead, Shefford and Chambly Railroad
- Stratford and Huron Railway
- Street Railway Construction Company
- Sydney Transfer and Storage
Read more about this topic: List Of Canadian National Railways Companies