| Abbreviation | Definition |
|---|---|
| USNU | US Department of Defense Navy |
| USNX | United States Department of Defense - Military Traffic Management Command ( Intraplant Service) |
| USNX | United States Navy |
| USPU | EXSIF Worldwide |
| USPX | United States Plastics Corporation |
| USPX | US Plastics Corporation |
| USPZ | United States Postal Service |
| USPZ | US Postal Service |
| USRC | Union Station Rail Corridor |
| USRX | US Railways |
| USSU | United Steel and Strip Corporation |
| USSX | United States Steel |
| USWX | U S A Waste Services, Incorporated |
| USWX | USA Waste Services |
| UTAH | Utah Railway |
| UTAH | Utah Railway Company |
| UTAX | United Transportation (Utah Transit Authority) |
| UTBX | Union Tank Car |
| UTCU | Stolt Tank Containers |
| UTCU | Stolt Tank Containers Incorporated |