| 1 | USR | US Army Aeronautical Services Agency | Callsign: US Army, | USA | AVCODES |
| 2 | USR | UTAH SOUTHERN RAILROAD COMPANY LLC | | | SCAC4 |
| 3 | USR | Utah Southern Railway Co. | | USA | TRAFFIC |
| 4 | USRA | URIBE SEGURA, ROSARIO | | | SCAC4 |
| 5 | USRC | U S RUBBER RECLAIMING INC | | | SCAC4 |
| 6 | USRD | U S ROAD FREIGHT EXPRESS INC | | | SCAC4 |
| 7 | USRE | U S RACETRONICS | | | SCAC4 |
| 8 | USRF | U S TRAFFIC INC | | | SCAC4 |
| 9 | USRI | UNIVERSAL SERVICE RECYCLING INC | | | SCAC4 |
| 10 | USRL | U S RAILWAYS INC | | | SCAC4 |
| 11 | USRP | U S RAIL CORPORATION LLC | | | SCAC4 |
| 12 | USRS | US RS, s.r.o. | | SK | VKM |
| 13 | USRT | U S ART CO INC | | | SCAC4 |
| 14 | USRV | U S TRANSPORT REPAIR & SERVICE INC | | | SCAC4 |
| 15 | USRX | United States Rubber Co. | 7/1923-7/1937 | | NAKINA |
| 16 | USRX | United States Rubber Products, Inc. | 4/1938 | | NAKINA |
| 17 | USRX | United States Rubber Co. | 1/1941-10/1966; eliminated 7/1967 | | NAKINA |
| 18 | USRX | Uniroyal, Inc. | added 7/1967; eliminated 4/1968 | | NAKINA |
| 19 | USRX | U.S. Railcar, Inc. | 1/1994 (not listed) | | NAKINA |
| 20 | USRX | US Railways Inc. | added 10/2003; eliminated 1/2004; 7/2005 (not listed) | | NAKINA |
| 21 | USRX | United States Rubber Products, Inc. | Apr-38 | | NRHS |
| 22 | USRX | United States Rubber Co. | 1/52-10/66; eliminated 7/67 | | NRHS |
| 23 | USRX | Uniroyal, Inc. | added 7/67; eliminated 4/68 | | NRHS |
| 24 | USRX | U.S. Railcar, Inc. | Jan-94 | | NRHS |
| 25 | USRX | *UNIROYAL, INC. [UNITED STATES RUBBER CO.] | | | PWRC |
| 26 | USRX | *U. S. ROAD & RAIL - MELVINDALE INC. | | | PWRC |
| 27 | USRX | +U. S. RAILWAYS, INC. [U.S. RAILCAR, INC.] | | | PWRC |
| 28 | USRX | US Railways | | | RSRV |
| 29 | USRX | US RAILWAYS INC | | | SCAC4 |
| 30 | USRZ | U. S. RECYCLING CO. | | | PWRC |
