| 1 | MRL | Aeromorelos S.A. de C.V. | Callsign: Aeromorelos, | MEX | AVCODES |
| 2 | MRL | Aeromorelos | | | ICAO1 |
| 3 | MRL | Montana RailLink, Inc. | added 4/1988; 1/1994-7/2005 | | NAKINA |
| 4 | MRL | Montana RailLink, Inc. | added 4/88; 1/94-7/2000 | | NRHS |
| 5 | MRL | MONTANA RAIL LINK, INC. [CODE FORMERLY ASSIGNED TO MEADOW RIVER LUMBER] | | | PWRC |
| 6 | MRL | Montana Rail Link | | | RSRV |
| 7 | MRL | MONTANA RAIL LINK INC | | | SCAC4 |
| 8 | MRL | Montana Raillink Inc. | | USA | TRAFFIC |
| 9 | MRL | Mendip Rail Limited | | UK | VKM |
| 10 | MRLC | MARTIN TRANSPORTATION SYSTEMS INC | | | SCAC4 |
| 11 | MRLD | MIRACLE, R L DIST CO INC | | | SCAC4 |
| 12 | MRLF | MCCROSKEY RANCHES LLC | | | SCAC4 |
| 13 | MRLG | MORNINGSTAR LOGISTICS LLC | | | SCAC4 |
| 14 | MRLH | MASON, ROBERT LOBSTER INC | | | SCAC4 |
| 15 | MRLI | MOTOR RAIL DELIVERY INC | | | SCAC4 |
| 16 | MRLJ | MARRLIN TRANSIT INC | | | SCAC4 |
| 17 | MRLL | M R L A TRANSPORTES S DE RL DE CV | | | SCAC4 |
| 18 | MRLM | Minneapolis, Red Lake and Manitoba Ry. Co. | 4/1938 | | NAKINA |
| 19 | MRLM | Minneapolis, Red Lake and Manitoba Ry. Co. | Apr-38 | | NRHS |
| 20 | MRLM | MINNEAPOLIS, RED LAKE & MANITOBA RWY. CO. | | | PWRC |
| 21 | MRLO | MERLO TRUCKING | | | SCAC4 |
| 22 | MRLQ | METRO LEASING LLC | | | SCAC4 |
| 23 | MRLR | MORALES TRUCKING | | | SCAC4 |
| 24 | MRLS | MATRIX LOGISTICS | | | SCAC4 |
| 25 | MRLT | MARLIN TRANSPORT LLC | | | SCAC4 |
| 26 | MRLT | Mineral Resources Limited | | AUS | TRAFFIC |
| 27 | MRLU | A P MOLLER | | | SCAC4 |
| 28 | MRLV | MIDTOWN RV LTD | | | SCAC4 |
| 29 | MRLX | Mid America Railcar Leasing LLC | added 10/2003; eliminated 4/2004; 7/2005 (not listed) | | NAKINA |
| 30 | MRLX | Morris & Co. Refrigerator Lines (Armour Car Lines) | 7/1923-7/1932 | | NAKINA |
| 31 | MRLX | Morris & Co. Refrigerator Line | 8/1920 | | NAKINA |
| 32 | MRLX | *ARMOUR CAR LINES [MORRIS & CO. REFRIGERATOR LINE] | | | PWRC |
| 33 | MRLX | +MID AMERICA RAILCAR LEASING | | | PWRC |
| 34 | MRLX | Mid America Railcar Leasing | | | RSRV |
| 35 | MRLX | MID AMERICA RAILCAR LEASING LLC | | | SCAC4 |
| 36 | MRLX | Mid-America Railcar Leasing | | USA | TRAFFIC |
| 37 | MRLY | MORLEY, T M INC | | | SCAC4 |
| 38 | MRLZ | MEADOW RIVER LUMBER | | | PWRC |
