| Abbreviation | Definition |
|---|---|
| MWCL | Midwest Coal Handling Incorporated |
| MWCX | Midwest Railcar Corporation |
| MWHX | Markwest Hydrocarbon Partners |
| MWHX | Markwest Hydrocarbon Partners Limited |
| MWLX | Midwest Locomotive Leasing and Sales |
| MWLZ | Madrigal-Wan Hai Lines Corporation |
| MWMX | Golden Leasing |
| MWMX | Midwest Mud (Golden Leasing) |
| MWPX | Murco Wall Products |
| MWR | Muncie and Western Railroad |
| MWR | Muncie and Western Railroad Company |
| MWRC | Mount Washington Railway |
| MWRC | Mount Washington Railway Company |
| MWRL | Hillvista Investment Company - Molalla Western Railway |
| MWRL | Molalla Western Railway (Hillvista Investment) |
| MWRR | Montana Western Railway |
| MWRR | Montana Western Railway Company Incorporated |
| MWRX | Midwest Rail |
| MWSX | General Electric Railcar Services Corporation |
| MWSX | Midwest Solvents (GE Rail Services) |