Liste des sigles de l'AAR débutant par U
# Liste des sigles de l'AAR débutant par U

## U

* UBTX - Union Camp Corporation
* UCCX - Union Carbide Canada, Ltd.
* UCEX - Union Electric Company
* UCFX - Union Carbide Corporation
* UCLX - Vulcan Minerals Company
* UCOX - Union Carbide Corporation
* UCPX - Essem Corporation
* UCR - Utah Coal Route
* UELX - United Equipment Leasing Associates; Archer Daniels Midland
* UFIX - Utility Fuels, Inc.
* UIWX - Riley Stoker Corporation
* UMP - Upper Merion and Plymouth Railroad
* UMPX - Upper Merion and Plymouth Leasing Company
* UNI - Unity Railways
* UNCX - Union Carbide Canada, Ltd.
* UNPX - PROCOR
* UNSX - Unitrain Services
* UO - Union Railroad (Oregon)
* UOCX - General American Transportation Corporation
* UP - Union Pacific Railroad
* UPAX - United Power Association
* UPFE - Pacific Fruit Express; Union Pacific Railroad
* UPM - Union Pacific Railroad (Milwaukee Road directed operations)
* UPOZ - United Parcel Service
* UPP - Union Pacific Railroad
* UPRX - Union Pacific Fruit Express Company
* UPSZ - United Parcel Service
* UPWZ - United Parcel Service
* UPY - Union Pacific Railroad
* URDX - United States Steel
* URR - Union Railroad (Pittsburgh, Pennsylvania)
* URHX - United Railway Historical Societies of New Jersey
* URTX - General American Transportation Corporation
* URY - Union Railway of Memphis
* USAX - Département de la Défense des États-Unis
* USBX - GE Rail Services
* USCX - William G. Simon
* USEX - Evans Railcar Leasing Company
* USGX - Union Sugar Company
* USIX - US Industrial Chemicals Company
* USLF - Burlington Northern Railroad
* USLX - Evans Railcar Leasing Company; GE Capital Railcar Services
* USNX - Département de la Défense des États-Unis
* USPX - US Plastics Corporation
* USRX - U.S. Railways, Inc.
* USSX - United States Steel
* UTAH - Utah Railway
* UTAX - United Transportation, Inc.
* UTBX - Union Tank Car Company
* UTCX - Union Tank Car Company
* UTLX - Union Tank Car Company
* UTPX - Union Texas Petroleum Corporation
* UTR - Union Transportation
* UTTX - Trailer Train Company
