| Abbreviation | Definition |
|---|---|
| CTUU | Container Trading Company |
| CTVX | Cleveland Terminal and Valley Railway |
| CTWU | Container Trading |
| CTWU | Container Trading Company |
| CTZZ | Continental Transportation |
| CTZZ | Continental Transportation Company |
| CUEX | Colorado-Utility Electric Assoc. |
| CUEX | Colorado-Utility Electric Association |
| CUNX | R. F. Cunningham and Company, Inc. |
| CUOH | Columbus and Ohio River Rail Road |
| CUOH | Columbus and Ohio River Railroad Company |
| CUR | Canine Underground Railroad |
| CURB | Curtis Bay Railroad |
| CURE | Consumers United for Rail Equity |
| CUST | Chicago Union Station |
| CUST | Chicago Union Station Company |
| CUT | Cincinnati Union Terminal |
| CUVA | Cuyahoga Valley Railway (ISG Cleveland Works Railway) |
| CUVA | Cuyahoga Valley Railway Company |
| CV | Central Vermont Railway (Canadian National Railway) |