| 1 | URT | Avia-Urartu | Callsign: Urartu Air, | AM | AVCODES |
| 2 | URTA | UNITED RIM TRANSPORT INC | | | SCAC4 |
| 3 | URTB | URTRUCKBROKER | | | SCAC4 |
| 4 | URTC | Union Refrigerator Transit Lines | a Division of the General American Transportation Corp. | USA | TRAFFIC |
| 5 | URTCo. | Union Refrigerator Transit Co. | 7/1935 | | NAKINA |
| 6 | URTS | URTRUCKSTUFF.COM LLC | | | SCAC4 |
| 7 | URTT | URUAMERICA TRUCKING LLC | | | SCAC4 |
| 8 | URTX | Union Refrigerator Transit Co. (previously U.R.T.Co.) | added 11/1934; 7/1935-4/1947 | | NAKINA |
| 9 | URTX | Union Refrigerator Transit Lines, a Division of the General American Transportation Corp. | 1/1950-4/1970; eliminated 10/1971 | | NAKINA |
| 10 | URTX | General American Transportation Corp., Freight Car Division | added 10/1971 | | NAKINA |
| 11 | URTX | General American Transportation Corp. | 1/1975-1/1980; eliminated 10/1992 | | NAKINA |
| 12 | URTX | Union Refrigerator Transit Lines, a Division of the General American Transportation Corp. | 4/38-4/70; eliminated 10/71 | | NRHS |
| 13 | URTX | General American Transportation Corp., Freight Car Division | added 10/71 | | NRHS |
| 14 | URTX | General American Transportation Corp. | 1/75-1/80; eliminated 10/92 | | NRHS |
| 15 | URTX | (GATX) RETIRED 08-19-92 ATP (1631) [UNION REFRIGERATOR TRANSIT LINES] | | | PWRC |
| 16 | URTX | Union Refrigerator Transit Lines (GATX) | | | RSRV |
