| Abbreviation | Definition |
|---|---|
| CYCY | Crystal City Railroad |
| CYCY | Crystal City Railroad Incorporated |
| CYDX | Conrad Yelvington Distributors |
| CYDX | Conrad Yelvington Distributors Incorporated |
| CYTX | Construcciones Y Trituaraciones de CV |
| CYTX | Construcciones y Trituaraciones S. A. De C. V. |
| CYX | American Cyanamid (Infinity Rail) |
| CZ | Coahuila and Zacatecas Railway |
| CZCX | Crown Zellerbach Corporation |
| CZRY | Carrizo Gorge Railway |
| CZZU | Cai International |
| D&RGW | Denver Rio Grande Western |
| D&RGW | Denver Rio Grande Western Railroad |
| D&RGW | Denver & Rio Grande Western |
| D&RGW | Denver & Rio Grande Western Railroad |
| D&TSL | Detroit and Toledo Shore Line Railroad |
| DA | Canadian Pacific Railway |
| DA | Dominion Atlantic Railway (Canadian Pacific Railway) |
| DACX | Darling and Company (VIP Tank Car Services) |
| DACX | VIP Tank Services |