| 1 | MWR | Raslan Air Service | Callsign: Raslan, | ET | AVCODES |
| 2 | MWR | Raslan Air Service | | | ICAO1 |
| 3 | MWR | Muncie and Western R.R. Co. | 4/1938-1/1994; eliminated 1/1995 | | NAKINA |
| 4 | MWR | Muncie and Western R.R. Co. | 4/38-1/94; eliminated 1/95 | | NRHS |
| 5 | MWR | MUNCIE & WESTERN RAILROAD COMPANY | | | PWRC |
| 6 | MWR | Muncie and Western Railroad | | | RSRV |
| 7 | MWR | Muncie and Western R.R. Co. | | USA | TRAFFIC |
| 8 | MWRA | MIDWES | | | SCAC4 |
| 9 | MWRB | MWR TRUCKING INC | | | SCAC4 |
| 10 | MWRC | Mount Washington Ry. Co. | 1/1975-7/2005 | | NAKINA |
| 11 | MWRC | Mount Washington Ry. Co. | 1/75-7/2000 | | NRHS |
| 12 | MWRC | MOUNT WASHINGTON RAILWAY CO. | | | PWRC |
| 13 | MWRC | Mount Washington Railway | | | RSRV |
| 14 | MWRC | MOUNT WASHINGTON RAILWAY CO | | | SCAC4 |
| 15 | MWRD | MIDWEST RUN INC | | | SCAC4 |
| 16 | MWRI | MAINE WREATHS INC | | | SCAC4 |
| 17 | MWRK | METALWORKING LUBRICANTS COMPANY | | | SCAC4 |
| 18 | MWRL | Hilvista Investment Co. d/b/a Molalia Western Ry. | 1/1994-7/2000 | | NAKINA |
| 19 | MWRL | Hilvista Investment Co. d/b/a Molalia Western Ry. | 1/94-7/2000 | | NRHS |
| 20 | MWRL | MOLALLA WESTERN RAILWAY (HILLVISTA INVESTMENT CO.) | | | PWRC |
| 21 | MWRL | Molalla Western Railway (Hillvista Investment) | | | RSRV |
| 22 | MWRN | MIDWEST TRANSPORT, INC | | | SCAC1 |
| 23 | MWRN | MIDWESTERN TRANSPORT INC | | | SCAC4 |
| 24 | MWRO | M & W TRANSPORTATION INC | | | SCAC4 |
| 25 | MWRO | MW Romania SA | | RO | VKM |
| 26 | MWRQ | MWR RACING LLC | | | SCAC4 |
| 27 | MWRR | Montana Western Ry. Co., Inc. | added 1/1987; 1/1994-7/2000; eliminated 1/2004; 7/2005 | | NAKINA |
| 28 | MWRR | Montana Western Ry. Co., Inc. | added 1/87; 1/94-7/2000 | | NRHS |
| 29 | MWRR | MONTANA WESTERN RAILWAY CO., INC. | | | PWRC |
| 30 | MWRR | Montana Western Railway | | | RSRV |
| 31 | MWRX | MidWest Rail Holdings, Inc. | 7/2000-7/2005 (not listed) | | NAKINA |
| 32 | MWRX | The Midwest Refining Co. | 8/1920-7/1923 | | NAKINA |
| 33 | MWRX | MidWest Rail Holdings, Inc. | Jul-00 | | NRHS |
| 34 | MWRX | *MIDWEST REFINING CO. | | | PWRC |
| 35 | MWRX | *MIDWEST RAIL HOLDINGS, INC. | | | PWRC |
| 36 | MWRX | MIDWEST RAIL HOLDINGS, INC. | | | PWRC |
| 37 | MWRX | Midwest Rail | | | RSRV |
| 38 | MWRY | Mineral Wells & Eastern Ry. Co. | added 7/1990; eliminated 4/1993; 1/1994 (not listed) | | NAKINA |
| 39 | MWRY | Mineral Wells & Eastern Ry. Co. | added 7/90; eliminated 4/93; 1/94 | | NRHS |
| 40 | MWRY | *RETIRED 10-26-92 ATP (522) | | | PWRC |
| 41 | MWRY | *MINERAL WELLS & EASTERN RAILWAY CO. | | | PWRC |
| 42 | MWRY | MOWREY AUCTION CO | | | SCAC4 |
| 43 | MWRY | Mineral Wells & Eastern Ry. Co. | | USA | TRAFFIC |
| 44 | MWRZ | METROPOLITAN WATER RECLAMATION DISTRICT | | | PWRC |
