| 1 | SMR | Samaritan Airevac | Callsign: Samaritan Air, | USA | AVCODES |
| 2 | SMR | Aircompany Somon Air LLC | IATA: 4J, Callsign: Somon Air, IATA designator changed to SZ. | TJ | AVCODES |
| 3 | SMR | Aircompany Somon Air LLC | IATA: SZ, Callsign: Somon Air, IATA Prefix: 413, IATA designator changed from 4J. | TJ | AVCODES |
| 4 | SMR | Somon Air | | | ICAO1 |
| 5 | SMR | South Manchuria Railway | | | TRAFFIC |
| 6 | SMR | SMR S.A. | | RO | VKM |
| 7 | SMRC | SAN MANUEL RAILROAD CO. | | | PWRC |
| 8 | SMRI | SMITH, R I COMPANY LIMITED | | | SCAC4 |
| 9 | SMRO | SIMON RIVER SPORTS | | | SCAC4 |
| 10 | SMRR | Sisseton Milbank R.R. Inc. | added 10/1989; 1/1994-7/2005 | | NAKINA |
| 11 | SMRR | Sisseton Milbank R.R. Inc. | added 10/89; 1/94-7/2000 | | NRHS |
| 12 | SMRR | SISSETON MILBANK RAILROAD | | | PWRC |
| 13 | SMRR | Sisseton Milbank Railroad | | | RSRV |
| 14 | SMRS | SOUTHERN MICHIGAN RAILROAD SOCIETY | | | PWRC |
| 15 | SMRS | S M R ASSOCIATES INC | | | SCAC4 |
| 16 | SMRT | SMRT Corporation | City: Singapore | SGP | TRAFFIC |
| 17 | SMRU | SOCIETE DE MAINTENANCE ET | | | SCAC4 |
| 18 | SMRW | SMR BESTWAYS EXPRESS LTD | | | SCAC4 |
| 19 | SMRX | Sampierre Chemical Corp. | added 10/1960; 4/1961; eliminated 4/1963 | | NAKINA |
| 20 | SMRX | Atlanta Chapter—National Railway Historical Society, Inc. | 7/2000-7/2005 (not listed) | | NAKINA |
| 21 | SMRX | Sampierre Chemical Corp. | added 10/60; 4/61 | | NRHS |
| 22 | SMRX | Atlanta Chapter--National Railway Historical Society, Inc. | Jul-00 | | NRHS |
| 23 | SMRX | *SAMPIERRE CHEMICAL CORP. | | | PWRC |
| 24 | SMRX | +STONE MOUNTAIN RAILROAD (ATLANTA CHAPTER , NATIONAL RAILWAY HISTORICAL SOCIETY) | | | PWRC |
| 25 | SMRX | Southeastern Railway Museum | | | RSRV |
| 26 | SMRX | ATLANTA CHAPTER - NATIONAL RAILWAY | | | SCAC4 |
| 27 | SMRY | SMART REFRIGERATED TRANSPORT | | | SCAC1 |
| 28 | SMRY | SMART REFRIGERATED TRANSPORT | | | SCAC4 |
