| 8801 | MTSX | MAX TRANSPORTATION SERVICE | | | PWRC |
| 8802 | MTSX | Max Transportation Service | | USA | TRAFFIC |
| 8803 | MTSY | MED TECH SOLUTIONS LLC | | | SCAC4 |
| 8804 | MTT | Mastair | Callsign: Blue Mast, | BIH | AVCODES |
| 8805 | MTT | Orion S.p.A. | | I | AVCODES |
| 8806 | MTTB | MULTI TRADE TERMINALS INC | | | SCAC4 |
| 8807 | MTTC | MATTIC INDUSTRIES LIMITED | | | SCAC4 |
| 8808 | MTTE | MARTIN TRUCKING 33 LLC | | | SCAC4 |
| 8809 | MTTG | MITCHELL TRUCKING | | | SCAC4 |
| 8810 | MTTH | MIDWEST TRANSPORT & TRUCKING INC | | | SCAC4 |
| 8811 | MTTL | MT TRANSPORTATION AND LOGISTICS SER | | | SCAC4 |
| 8812 | MTTM | MONTANA TRUCKING INC | | | SCAC4 |
| 8813 | MTTO | MOTTO TRUSS INC | | | SCAC4 |
| 8814 | MTTP | MTS TRANSPORTATION INC | | | SCAC4 |
| 8815 | MTTQ | MACAO TAK TRANSPORT INC | | | SCAC4 |
| 8816 | MTTS | MT TRANSPORTES Y SERVICIOS | | | SCAC4 |
| 8817 | MTTU | Mariupol Tram-Trolleybus Administration | City: Mariupol | UA | TRAFFIC |
| 8818 | MTTX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 8819 | MTTX | Trailer Train Co. | added 10/1964; 7/1965-1/1980; eliminated 1/1992 | | NAKINA |
| 8820 | MTTX | Trailer Train Co. | added 10/1964 | | NAKINA |
| 8821 | MTTX | Trailer Train Co. (FM flat cars for general service) | 7/1965-10/1968 | | NAKINA |
| 8822 | MTTX | Trailer Train Co. (60' flat cars with stake pockets and lading strap anchors for general service; or 85' flat cars with 16 stake pockets, 8 per side, for transporting long pipe) | 4/1970-7/1985 | | NAKINA |
| 8823 | MTTX | Trailer Train Co./TTX Co. (60' flat cars with stake pockets for general service; or 85' flat cars with sixteen stake pockets, 8 per side, for transporting long pipe, also 89' cars installed with bulkheads) | 10/1991-1/1994 | | NAKINA |
| 8824 | MTTX | TTX Co. (60' flat cars with stake pockets for general service; or 85' flat cars with sixteen stake pockets, 8 per side, for transporting long pipe, also 89' cars installed with bulkheads, equipped with end of car cush.) | 7/2000 | | NAKINA |
| 8825 | MTTX | Trailer Train Co. | Jul-65 | | NRHS |
| 8826 | MTTX | Trailer Train Co. (FM flat cars for general service) | 10/66-10/68 | | NRHS |
| 8827 | MTTX | Trailer Train Co. | Apr-70 | | NRHS |
| 8828 | MTTX | Trailer Train Co. (60' flat cars with stake pokcets and lading strap anchors for general service; or 85' flat cars with 16 stake pockets, 8 per side, for transporting long pipe) | 1/75-1/80 | | NRHS |
| 8829 | MTTX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 8830 | MTTX | TTX Co. | added 1/92 | | NRHS |
| 8831 | MTTX | TTX Co. (60' flat cars with stake pockets for general service; or 85' flat cars with sixteen stake pockets, 8 per side, for transporting long pipe, also 89' cars installed with bulkheads) | Jan-94 | | NRHS |
| 8832 | MTTX | TTX Co. (60' flat cars with stake pockets for general service; or 85' flat cars with sixteen stake pockets, 8 per side, for transporting long pipe, also 89' cars installed with bulkheads, equipped with end of car cush.) | Jul-00 | | NRHS |
| 8833 | MTTX | TTX COMPANY | | | PWRC |
| 8834 | MTTX | Trailer Train (TTX Corporation) | | | RSRV |
| 8835 | MTTX | TTX COMPANY | | | SCAC4 |
| 8836 | MTTZ | MT. TOM | | | PWRC |
| 8837 | MTU | Middle Tennessee State University (MTSU) | Callsign: Blue Raider, | USA | AVCODES |
| 8838 | MTUA | MANLEY TRANSPORTATION LLC | | | SCAC4 |
| 8839 | MTUE | MT TRUCKING | | | SCAC4 |
| 8840 | MTUF | MACLEANS TRUCKING LTD | | | SCAC4 |
| 8841 | MTUK | MERCY TRUCK BROKERS INC | | | SCAC4 |
| 8842 | MTUM | MONARREZ TRUCKING | | | SCAC4 |
| 8843 | MTUN | METRACO TRANSPORTATION COMPANY | | | SCAC4 |
| 8844 | MTUQ | MTR TRUCKING | | | SCAC4 |
| 8845 | MTUS | M TWO (M2) LOGISTICS INC | | | SCAC4 |
| 8846 | MTUU | ROLLS ROYCE SOLUTIONS AMERICA INC. | | USA | BIC |
| 8847 | MTUU | MTU Onsite Energy Corporation | | | RSRV |
| 8848 | MTUY | MERCURY TRUCKING SYSTEM | | | SCAC4 |
| 8849 | MTV | Mountain Valley Air Service, Inc. | Callsign: Mountain Valley, | USA | AVCODES |
| 8850 | MTV | Mountain Valley Air Service | | | ICAO1 |
| 8851 | MTVC | MONTANA TRANSPORT | | | SCAC4 |
| 8852 | MTVE | M T EXPRESS LLC | | | SCAC4 |
| 8853 | MTVH | MCTAVISH STEEL WORKS LTD | | | SCAC4 |
| 8854 | MTVI | MDS TRUCKING V INC | | | SCAC4 |
| 8855 | MTVJ | MERLES TRUCKING | | | SCAC4 |
| 8856 | MTVL | MOUNTAIN VALLEY EXPRESS CO | | | SCAC1 |
| 8857 | MTVL | MOUNTAIN VALLEY EXPRESS CO INC | | | SCAC4 |
| 8858 | MTVM | MIDWEST TRANSIT INC | | | SCAC4 |
| 8859 | MTVP | MTS TRUCKING SERVICES | | | SCAC4 |
| 8860 | MTVT | MT. VERNON TERMINAL RAILWAY | | | PWRC |
| 8861 | MTVU | CONTAINERS MTV | | I | BIC |
| 8862 | MTVU | P & F PARTNERS AND FRIENDS | | | SCAC4 |
| 8863 | MTVY | MILLENNIUM TOWING & RECOVERY INC | | | SCAC4 |
| 8864 | MTW | Mauritania Airways | Callsign: Mauritania Airways, | RIM | AVCODES |
| 8865 | MTW | Tomahawk Ry., Limited Partnership | added 4/1992; 1/1994 (not listed) | | NAKINA |
| 8866 | MTW | Marinette, Tomahawk & Western R.R. Co. | 1/1975-1/1980; eliminated 4/1992 | | NAKINA |
| 8867 | MTW | Marinette, Tomahawk & Western R.R. Co. | 1/75-1/80; eliminated 4/92 | | NRHS |
| 8868 | MTW | Tomahawk Ry., Limited Partnership | added 4/92; 1/94 | | NRHS |
| 8869 | MTW | TOMAHAWK RAILWAY [MARINETTE, TOMAHAWK & WESTERN RAILROAD COMPANY] | | | PWRC |
| 8870 | MTW | Marinette, Tomahawk and Western Railroad | | | RSRV |
| 8871 | MTW | Marinette, Tomahawk and Western Railroad | | USA | TRAFFIC |
| 8872 | MTW | MTW Rail AB | | SE | VKM |
| 8873 | MTWC | MANGAN TEAM FARMS LIMITED | | | SCAC4 |
| 8874 | MTWC | Montreal Tramways Company | | CDN | TRAFFIC |
| 8875 | MTWE | MUNDIES TOWING & RECOVERY | | | SCAC4 |
| 8876 | MTWG | MITCHENER TRANSPORT | | | SCAC4 |
| 8877 | MTWI | MAIERS TRANSPORT & WAREHOUSING INC | | | SCAC4 |
| 8878 | MTWM | MCI TRUCKING INC | | | SCAC4 |
| 8879 | MTWN | MILLTOWN TRUCKING CO LTD | | | SCAC4 |
| 8880 | MTWQ | M TWO (M2) TRANSPORT INC | | | SCAC4 |
| 8881 | MTWT | MOUNTAIN WEST MOVING & STORAGE | | | SCAC4 |
| 8882 | MTWV | METEOR TOWING INC | | | SCAC4 |
| 8883 | MTX | Multi Taxi, S.A. de C.V. | Callsign: Multitaxi, | MEX | AVCODES |
| 8884 | MTX | Multi Taxi | | | ICAO1 |
| 8885 | MTX | Tomahawk Ry., Limited Partnership | eliminated 4/1993 | | NAKINA |
| 8886 | MTX | North American Car Corp. | added 7/1955; eliminated 10/1957; added 1/1958; eliminated 7/1959 | | NAKINA |
| 8887 | MTX | Mather Stock Car Co. | added 7/1954; 7/1954; eliminated 7/1955 | | NAKINA |
| 8888 | MTX | Morrell Tank Line | eliminated 7/1954 | | NAKINA |
| 8889 | MTX | Morrell Tank Line (T.H. Foster, Trustee) | 7/1937-1/1952 | | NAKINA |
| 8890 | MTX | Morrell Tank Line (Morrell Refrigerator Car Co.) | 7/1930-7/1935 | | NAKINA |
| 8891 | MTX | Morrell Tank Line (Morrell Refrigerator Line) | 8/1920-7/1923 | | NAKINA |
| 8892 | MTX | Morrell Tank Line (Morrell Refrigerator Car Co.) | Apr-38 | | NRHS |
| 8893 | MTX | Morrell Tank Line (T.H. Foster, Trustee) | Jan-52 | | NRHS |
| 8894 | MTX | Mather Stock Car Co. | eliminated 7/55 | | NRHS |
| 8895 | MTX | North American Car Corp. | added 7/55; eliminated 10/57; added 1/58; eliminated 7/59 | | NRHS |
| 8896 | MTX | Tomahawk Ry., Limited Partnership | eliminated 4/93 | | NRHS |
| 8897 | MTX | *MORRELL TANK LINE [JOHN MORRELL & CO.] (NCCo [MATHER STOCK CAR CO.]) | | | PWRC |
| 8898 | MTX | *TOMAHAWK RAILWAY, LP | | | PWRC |
| 8899 | MTXA | MEGA-TEX XPRESS | | | SCAC4 |
| 8900 | MTXB | MTS EXPRESS LLC | | | SCAC4 |
