| 2001 | USLX | (NATX) GENERAL ELECTRIC RAIL SERVICES CORP. [ITEL RAIL CORP.; EVANS RAILCAR LEASING; UNITED STATES RAILWAY LEASING CO.] | | | PWRC |
| 2002 | USLX | Evans Railcar Leasing (GE Rail Services) | | | RSRV |
| 2003 | USLX | GENERAL ELECTRIC RAILCAR SERVICES C | | | SCAC4 |
| 2004 | USLY | UNIQUE SERVICES LOGISTICS | | | SCAC4 |
| 2005 | USLZ | UNITED STATES LINES, INC. | | | PWRC |
| 2006 | USLZ | United States Lines | | | RSRV |
| 2007 | USLZ | UNITED STATES LINES INC | | | SCAC4 |
| 2008 | USM | Air Mobility Command | IATA: MC, | USA | AVCODES |
| 2009 | USMB | USMC TRANSPORT LLC | | | SCAC4 |
| 2010 | USMC | USMS LOGISTICS LLC | | | SCAC4 |
| 2011 | USMC | United States Marine Corps | | USA | TRAFFIC |
| 2012 | USMG | USM LOGISTICS | | | SCAC4 |
| 2013 | USML | UNIVAN SHIP MANAGEMENT LIMITED | | | SCAC4 |
| 2014 | USMM | USA TRUCK INC (INTERMODAL | | | SCAC4 |
| 2015 | USMN | U. S. STEEL MINING RAILROAD | | | PWRC |
| 2016 | USMN | U-SHIP MARITIME SERVICES INC | | | SCAC4 |
| 2017 | USMR | UNITED STATES METALS REFINING | | | PWRC |
| 2018 | USMS | UNIVERSA | | | SCAC4 |
| 2019 | USMU | UNITED STATES MARINE CORPS | | USA | BIC |
| 2020 | USMU | U.S. DEPARTMENT OF DEFENSE - MARINE CORPS | | | PWRC |
| 2021 | USMU | US Department of Defense Marine Corps | | | RSRV |
| 2022 | USMU | U S DEPARTMENT OF DEFENSE-MARINE CO | | | SCAC4 |
| 2023 | USMV | USACAN MEDIA DIST SRV CORP | | | SCAC4 |
| 2024 | USMX | U.S. Steel Mining Co., Inc. | 7/2000-7/2005 (not listed) | | NAKINA |
| 2025 | USMX | U.S. Steel Mining Co., Inc. | Jul-00 | | NRHS |
| 2026 | USMX | U.S. STEEL MINING COMPANY, INC. | | | PWRC |
| 2027 | USMX | US Steel Mining | | | RSRV |
| 2028 | USMZ | U.S. DEPARTMENT OF DEFENSE - MARINE CORPS | | | PWRC |
| 2029 | USN | Smarkand Aero Servise | | | ICAO1 |
| 2030 | USN | United States Navy | | USA | TRAFFIC |
| 2031 | USNA | U S NATIONAL INC | | | SCAC4 |
| 2032 | USNC | UNITED STATES NAVIGATION CO INC | | | PWRC |
| 2033 | USNG | U.S. DEPARTMENT OF DEFENSE/U.S. NAV | | | SCAC4 |
| 2034 | USNK | US INK (DIVISION OF SUN | | | SCAC4 |
| 2035 | USNS | U S TRANSPORTATION SERVICES INC | | | SCAC4 |
| 2036 | USNT | U S TRANSPORTATION CO | | | SCAC4 |
| 2037 | USNU | UNITED STATES NAVY | | USA | BIC |
| 2038 | USNU | U.S. NAVY | | | PWRC |
| 2039 | USNU | US Department of Defense Navy | | | RSRV |
| 2040 | USNU | U S DEPARTMENT OF DEFENSE-NAVY | | | SCAC4 |
| 2041 | USNV | U.S. DEPARTMENT OF DEFENSE/U.S. NAV | | | SCAC4 |
| 2042 | USNX | United States Navy | 7/1935 | | NAKINA |
| 2043 | USNX | United States Navy (Tanks), Bureau of S. & A. | 7/1937-1/1950 | | NAKINA |
| 2044 | USNX | Dept. of the Navy, Bureau of S. & A. | 1/1952-10/1957; eliminated 4/1960 | | NAKINA |
| 2045 | USNX | Dept. of Defense, Military Traffic Management Agency | added 4/1960; 4/1961; eliminated 4/1962 | | NAKINA |
| 2046 | USNX | Dept. of Defense, Defense Traffic Management Service | added 4/1962; eliminated 7/1965 | | NAKINA |
| 2047 | USNX | Dept. of Defense, Military Traffic Management and Terminal Service | added 7/1965; 7/1965-4/1970; eliminated 10/1974 | | NAKINA |
| 2048 | USNX | Dept. of Defense, Military Traffic Management Command | added 10/1974; 1/1975; eliminated 7/1975 | | NAKINA |
| 2049 | USNX | Dept. of Defense, Military Traffic Management Command (intra-plant service) | 1/1980; 1/1994-7/2005 (not listed) | | NAKINA |
| 2050 | USNX | United States Navy | Apr-38 | | NRHS |
| 2051 | USNX | Dept. of the Navy, Bureau of S. & A. | 1/52-10/57 | | NRHS |
| 2052 | USNX | U.S. Navy | Apr-61 | | NRHS |
| 2053 | USNX | Dept. of Defense, Military Traffic Management Agency | eliminated 4/62 | | NRHS |
| 2054 | USNX | Dept. of Defense, Defense Traffic Management Service | added 4/62; eliminated 7/65 | | NRHS |
| 2055 | USNX | Dept. of Defense, Military Traffic Management and Terminal Service | added 7/65; 7/65-4/70 | | NRHS |
| 2056 | USNX | Dept. of Defense, Military Traffic Management Command | 1/75; eliminated 7/75 | | NRHS |
| 2057 | USNX | Dept. of Defense, Military Traffic Management Command (intra-plant service) | 1/80-7/2000 | | NRHS |
| 2058 | USNX | U.S. DEPARTMENT OF DEFENSE - MILITARY TRAFFIC MANAGEMENT COMMAND (INTRA PLANT SERVICE) | | | PWRC |
| 2059 | USNX | United States Navy | | | RSRV |
| 2060 | USNX | DEPT OF ARMY MIL TRFC MGMT & TERM S | | | SCAC4 |
| 2061 | USNX | United States Navy | | USA | TRAFFIC |
| 2062 | USNZ | U.S. DEPARTMENT OF DEFENSE - NAVY | | | PWRC |
| 2063 | USOI | U S ONE (1) EXPRESS INC | | | SCAC4 |
| 2064 | USON | US ONE (1) LOGISTICS LLC | | | SCAC4 |
| 2065 | USOP | US ONE (1) CORP | | | SCAC4 |
| 2066 | USOS | U S CONTAINER SYSTEMS INC | | | SCAC4 |
| 2067 | USOX | War Dept., U.S.A., Quartermaster Corps | 1/1943 | | NAKINA |
| 2068 | USOX | War Dept., U.S.A., Office of the Chief of Transportation | 1/1945-4/1947 | | NAKINA |
| 2069 | USOX | Dept. of the Army, Office of the Chief of Transportation, Movements Division, Tank Car Section | 1/1950-1/1952 | | NAKINA |
| 2070 | USOX | Dept. of the Army | added 7/1953 | | NAKINA |
| 2071 | USOX | Dept. of the Army, Office of the Chief of Transportation, Railway Transport Service Division | 7/1954 | | NAKINA |
| 2072 | USOX | Department of the Army, Transportation Materiel Command, Marietta, Pennsylvania | eliminated 10/1955 | | NAKINA |
| 2073 | USOX | Department of the Army, Transportation Supply and Maintenance Command, St. Louis 1, Missouri | added 10/1955; eliminated 10/1956 | | NAKINA |
| 2074 | USOX | Dept. of the Army, Office of the Chief of Transportation, Movements Division, Tank Car Section | Jan-52 | | NRHS |
| 2075 | USOX | U.S. DEPARTMENT OF DEFENSE - ARMY | | | PWRC |
| 2076 | USOY | USA OPPORTUNITY | | | SCAC4 |
| 2077 | USOZ | U. S. STEEL MINNESOTA OIL OPERATION | | | PWRC |
| 2078 | USP | U.S. DEPARTMENT OF DEFENSE - PORTSMOUTH NH NAVAL YARD | | | PWRC |
| 2079 | USPC | (UPCX) USPCI, INC. | | | PWRC |
| 2080 | USPC | US PATTERN CO INC | | | SCAC4 |
| 2081 | USPF | UNITED STATES PINE FOUNDRY | | | PWRC |
| 2082 | USPF | United States Pipe & Foundry Corporation | | USA | TRAFFIC |
| 2083 | USPM | USA PETROLEUM CORPORATION | | | SCAC4 |
| 2084 | USPS | United States Postal Service | | | SCAC2 |
| 2085 | USPS | UNITED STATES POSTAL SERVICE | | | SCAC4 |
| 2086 | USPU | EXSIF WORLDWIDE | | USA | BIC |
| 2087 | USPU | EXSIF Worldwide | | | RSRV |
| 2088 | USPU | EXSIF WORLDWIDE | | | SCAC4 |
| 2089 | USPX | U.S. Phosphoric Products Corp. | 7/1935-4/1938 | | NAKINA |
| 2090 | USPX | U.S. Phosphoric Products-Division Tennessee Corp. | 1/1941-1/1946 | | NAKINA |
| 2091 | USPX | U.S. Pipe and Foundry Co. | added 1/1960; 4/1961-10/1966; eliminated 4/1970 | | NAKINA |
| 2092 | USPX | U.S. Plastics Corp. | 1/1994-7/2005 (not listed) | | NAKINA |
| 2093 | USPX | U.S. Phosphoric Products Corp. | Apr-38 | | NRHS |
| 2094 | USPX | U.S. Pipe and Foundry Co. | added 1/60; 4/61-10/66; eliminated 4/70 | | NRHS |
| 2095 | USPX | U.S. Plastics Corp. | 1/94-7/2000 | | NRHS |
| 2096 | USPX | *U. S. PHOSPHORIC PRODUCTS, DIV. TENNESSEE CORP. | | | PWRC |
| 2097 | USPX | *U. S. PIPE & FOUNDRY CO. | | | PWRC |
| 2098 | USPX | *U. S. PLASTICS CORPORATION | | | PWRC |
| 2099 | USPX | US Plastics Corporation | | | RSRV |
| 2100 | USPX | US PLASTICS CORPORATION | | | SCAC4 |
