| 1 | MKT | Union Pacific R.R. Co. | added 4/1997; 7/2000-7/2005 | | NAKINA |
| 2 | MKT | Missouri Pacific System | added 1/1990; 1/1994; eliminated 4/1997 | | NAKINA |
| 3 | MKT | Missouri-Kansas-Texas R.R. Co. | 1/1941-10/1966 & 1/1975-1/1980; eliminated 1/1990 | | NAKINA |
| 4 | MKT | Missouri-Kansas-Texas R.R. Co. | 1/52-10/66 & 1/75-1/80; eliminated 1/90 | | NRHS |
| 5 | MKT | Missouri Pacific System | added 1/90; 1/94; eliminated 4/97 | | NRHS |
| 6 | MKT | Union Pacific R.R. Co. | added 4/97; 7/2000 | | NRHS |
| 7 | MKT | UNION PACIFIC RAILROAD CO. [MISSOURI PACIFIC; MISSOURI, KANSAS & TEXAS RWY.; M.K. & T. LINES} | | | PWRC |
| 8 | MKT | Missouri-Kansas-Texas Railroad (Union Pacific Railroad) | | | RSRV |
| 9 | MKT | Missouri-Kansas-Texas Railroad Company | | USA | TRAFFIC |
| 10 | MKT | Majkoltrans Sp. Z o.o. | | PL | VKM |
| 11 | MKTB | MCKENZIE TRUCKING CO | | | SCAC4 |
| 12 | MKTC | MACK TRUCKING | | | SCAC4 |
| 13 | MKTJ | MK TRUCKING | | | SCAC4 |
| 14 | MKTK | MANKE TRUCKING, INC | | | SCAC1 |
| 15 | MKTK | MANKE TRUCKING INCORPORATED | | | SCAC4 |
| 16 | MKTL | MACKIE TRANSPORT LIMITED (DIV OF MA | | | SCAC4 |
| 17 | MKTM | MCKINSEY TRUCKING | | | SCAC4 |
| 18 | MKTR | MIKES TOWING & RECOVERY INC | | | SCAC4 |
| 19 | MKTR | Międzygminna Komunikacja Tramwajowa Sp. | It was a transport company based in Łódź , established in 1993 as the continuator of the tradition of over a hundred years of Łódź suburban tram transport. | PL | TRAFFIC |
| 20 | MKTS | MKT SERVICES | | | SCAC4 |
| 21 | MKTT | Union Pacific R.R. Co. | added 4/1997; 7/2000-7/2005 | | NAKINA |
| 22 | MKTT | Missouri Pacific System | added 1/1990; 1/1994; eliminated 4/1997 | | NAKINA |
| 23 | MKTT | Missouri-Kansas-Texas R.R. Co. | 7/1965-10/1966 & 1/1975-1/1980; eliminated 1/1990 | | NAKINA |
| 24 | MKTT | Missouri-Kansas-Texas R.R. Co. of Texas | 4/1938-4/1961 | | NAKINA |
| 25 | MKTT | Missouri-Kansas-Texas R.R. Co. of Texas (M.-K.-T. Lines) | 7/1923-7/1936 | | NAKINA |
| 26 | MKTT | Missouri, Kansas & Texas Ry. of Texas (M. K. & T. Lines) | 8/1920 | | NAKINA |
| 27 | MKTT | Missouri-Kansas-Texas R.R. Co. of Texas | 4/38-4/61 | | NRHS |
| 28 | MKTT | Missouri-Kansas-Texas R.R. Co. | 7/65-10/66 & 1/75-1/80; eliminated 1/90 | | NRHS |
| 29 | MKTT | Missouri Pacific System | added 1/90; 1/94; eliminated 4/97 | | NRHS |
| 30 | MKTT | Union Pacific R.R. Co. | added 4/97; 7/2000 | | NRHS |
| 31 | MKTT | UNION PACIFIC RAILROAD CO. [MISSOURI PACIFIC; MISSOURI, KANSAS & TEXAS RWY.; M.K. & T. LINES} | | | PWRC |
| 32 | MKTT | Missouri-Kansas-Texas Railroad (Union Pacific Railroad) | | | RSRV |
| 33 | MKTU | MK REFTRANS CO. LTD. | | RUS | BIC |
| 34 | MKTV | MARK THE MOVER INC | | | SCAC4 |
| 35 | MKTW | MACK TRUCKING INC | | | SCAC4 |
| 36 | MKTY | MCCORKLE TRUCKING SERVICE | | | PWRC |
| 37 | MKTZ | UP [MISSOURI PACIFIC RAILROAD] | | | PWRC |
| 38 | MKTZ | Missouri-Kansas-Texas Railroad (Union Pacific Railroad) | | | RSRV |
| 39 | MKTZ | UNION PACIFIC RAILROAD COMPANY | | | SCAC4 |
