| 1 | COLX | Alliant Energy | added 4/2000; 7/2000-7/2005 | | NAKINA |
| 2 | COLX | Wisconsin Power & Light Co. | 1/1994 (not listed) | | NAKINA |
| 3 | COLX | North American Car Corp. | added 1/1966; 10/1966-1/1980; eliminated 7/1982 | | NAKINA |
| 4 | COLX | Collins Construction Co. | 1/1950-1/1952; eliminated 7/1953 | | NAKINA |
| 5 | COLX | Collins Construction Co. | Jan-52 | | NRHS |
| 6 | COLX | North American Car Corp. | added 1/66; 10/66-1/80; eliminated 7/82 | | NRHS |
| 7 | COLX | Wisconsin Power & Light Co. | Jan-94 | | NRHS |
| 8 | COLX | Alliant Energy | added 4/2000; 7/2000 | | NRHS |
| 9 | COLX | *COLLINS CONSTRUCTION CO. | | | PWRC |
| 10 | COLX | *NORTH AMERICAN CAR CORP. | | | PWRC |
| 11 | COLX | +ALLIANT ENERGY (WISX) (WISCONSIN POWER & LIGHT COMPANY) | | | PWRC |
| 12 | COLX | Collins Construction Co. (Alliant Energy) | | | RSRV |
| 13 | COLX | ALLIANT ENERGY | | | SCAC4 |