| 1 | MWEX | Union Refrigerator Transit Lines, a Division of General American Transportation Corp. | 7/1965-4/1970; eliminated 4/1971 | | NAKINA |
| 2 | MWEX | Mars Inc. | 4/1963 | | NAKINA |
| 3 | MWEX | Union Refrigerator Transit Lines | added 4/1963 | | NAKINA |
| 4 | MWEX | Union Refrigerator Transit Lines, a Division of General American Transportation Corp. | 1/1950-4/1961 | | NAKINA |
| 5 | MWEX | Mars Inc. | 7/1932-7/1935 | | NAKINA |
| 6 | MWEX | Union Refrigerator Transit Co. | 7/1937-4/1947 | | NAKINA |
| 7 | MWEX | Mars Inc. | Apr-38 | | NRHS |
| 8 | MWEX | Union Refrigerator Transit Lines, a Division of the General American Transportation Corp. | 1/52-4/70; eliminated 4/71 | | NRHS |
| 9 | MWEX | *UNION REFRIGERATOR TRANSIT LINES, DIV. GENERAL AMERICAN TRANSPORTATION CORP. (MARS, INC.) | | | PWRC |
| 10 | MWEX | *MINERAL WELLS & EASTERN | | | PWRC |