| 1 | MWDA | MOTORWORKS DRILLING SOLUTIONS | | | SCAC4 |
| 2 | MWDD | MIDWEST DEDICATED SERVICES INC | | | SCAC4 |
| 3 | MWDE | MIDWES | | | SCAC4 |
| 4 | MWDH | MOUNTAIN WEST COMMERCIAL DRIVING SC | | | SCAC4 |
| 5 | MWDR | MIDWEST INDUSTRIES INC | | | SCAC4 |
| 6 | MWDS | MILWAUKEE DELIVERY SERVICE INC | | | SCAC4 |
| 7 | MWDX | Mid-West Despatch Car Co. | 7/1930-1/1943 | | NAKINA |
| 8 | MWDX | Mid-West Despatch Car Co. (Nickel Plate-Lackawanna Dairy Line) | 7/1923 | | NAKINA |
| 9 | MWDX | Mid-West Despatch Car Co. | 8/1920 | | NAKINA |
| 10 | MWDX | Mid-West Despatch Car Co. | Apr-38 | | NRHS |
| 11 | MWDX | MID-WEST DESPATCH CAR CO. | | | PWRC |
