| Abbreviation | Definition |
|---|---|
| CARR | Carrollton Railroad |
| CARX | Cargo Carriers (Lamson and Sessions) |
| CARX | Lamson and Sessions |
| CARZ | Anton Caratan and Son |
| CARZ | Anton Caraton and Son |
| CASO | Canada Southern Railway (Canadian Pacific Railway) |
| CASO | Canadian Pacific Railway (CASO) |
| CATS | Cumbres And Toltec Scenic Railroad |
| CATU | CATU Containers |
| CATU | CATU Containers S. A. |
| CAXU | Container Applications International |
| CAXU | Container Applications International Incorporated |
| CAZU | Cai International |
| CB&Q | Chicago Burlington Quincy |
| CB&Q | Chicago Burlington & Quincy |
| CB&Q | Chicago, Burlington, Quincy |
| CB&Q | Chicago, Burlington, & Quincy |
| CB&QRR | CHICAGO BURLINGTON & QUINCY Railroad |
| CBC | Carbon County Railway (Chemin de fer Baie des Chaleurs) |
| CBC | Chemins de fer Baie des Chaleurs Incorporated |