List of reporting marks: M

M

 * MAA - Magma Arizona Railroad
 * MAAX - Maxx Leasing Company
 * MACX - Mac Acquisitions
 * MADU - Magnum Speditionsgelleshaft
 * MAEU - Maersk Lines
 * MAGX - Magnimet, Monroe Scrap Division
 * MAIX - Macon Iron and Paper Stock
 * MAJU - Malaysian International Shipping Corporation
 * MALX - Mid-America Locomotive and Car Repair
 * MALZ - American President Lines
 * MANX - Manchester Gas Company; Williams Energy Ventures
 * MAPX - MAPCO Products Company; Williams Energy Ventures
 * MARX - MidAmerican Energy Corporation
 * MARZ - MARTRAC
 * MASX - GE Rail Services
 * MATU - Matson Navigation Company
 * MATX - Merchants Investment Company
 * MATZ - Matson Navigation Company
 * MAW - Maumee and Western Railroad
 * MAXU - Maxu Containers
 * MAXX - MidAmerican Energy Company
 * MAYW - Maywood and Sugar Creek
 * MB  - Meridian & Bigbee Railroad
 * MBBX - Tank Car Services
 * MBCX - MBCX Leasing
 * MBFX - MBF Industries
 * MBIX - Morse Brothers
 * MBKX - MRC Rail Services
 * MBLX - Exxon-Mobil Corporation
 * MBPX - MacMillan-Bloedell
 * MBRR - Meridian & Bigbee Railroad
 * MBSX - Mid-South Bulk Services
 * MBT - Marianna and Blountstown Railroad
 * MBTX - Massachusetts Bay Transportation Authority
 * MC  - Michigan Central Railroad; New York Central Railroad; Penn Central; Maine Coast Railroad (1991-2000); Massachusetts Coastal Railroad (2007-)
 * MCCX - Mount Vernon Coal Transfer Company; Mount Vernon Transfer Terminal
 * MCDX - Redland Worth Corporation; Sunbelt Cement
 * MCER - Massachusetts Central Railroad
 * MCEU - Massachusetts Central Railroad
 * MCEZ - Massachusetts Central Railroad
 * MCHX - Trinity Rail Management
 * MCIX - Mobley Company (Applied Chemicals Division)
 * MCLR - McLaughlin Line Railroad
 * MCLX - Morrison Car Leasing
 * MCMU - Management Control and Maintenance
 * MCMX - MC Rail Services
 * MCPX - Monsanto Company; Solutia
 * MCR - McCloud River Railroad; McCloud Railway
 * MCRR - Monongahela Connecting Railroad
 * MCRX - Marcus Rail Transport
 * MCRY - Mid Continent Railway
 * MCSA - Moscow, Camden and San Augustine Railroad
 * MCSU - China Ocean Shipping Company
 * MCTA - Minnesota Central Railroad
 * MCTX - Modern Continental Construction Company
 * MCVX - Massachusetts Call Volunteer Firefighters' Association
 * MD  - Municipal Docks
 * MDAX - Merchants Despatch Transportation Corporation
 * MDCX - Mexicana De Cobre, SA de CV
 * MDDE - Maryland and Delaware Railroad
 * MDDX - Old Line Holding Company
 * MDIX - Modern Dispersions
 * MDKX - Gardau MRM Steel (Mandak Metal Processors Division)
 * MDLR - Midland Terminal Company
 * MDP - Mexican Pacific Railroad (Ferrocarril Mexicano del Pacifico)
 * MDR - Kansas City Southern Railway
 * MDS - Meridian Southern Railway
 * MDSB - Burlington Northern Railroad
 * MDSZ - Medspan Shipping Service
 * MDT - Merchants Despatch Transportation Corporation
 * MDTX - Merchants Despatch Refrigerator Line
 * MDW - Minnesota, Dakota & Western Railway
 * MDWU - Minnesota, Dakota & Western Railway
 * MDWZ - Minnesota, Dakota & Western Railway
 * ME  - Morristown & Erie Railway
 * MEC - Maine Central Railroad; Pan Am Railways
 * MECX - Trinity Rail Management
 * MEDU - Mediterranean Shipping Company
 * MEFX - MexFresh
 * MEFZ - MexFresh
 * MELX - Sunbelt Cement
 * MEPX - McGraw-Edison Company
 * MERR - Maine Eastern Railroad
 * MERX - Merco
 * MESX - Mears/CPG
 * MET - Modesto and Empire Traction Company
 * METW - Municipality of East Troy Wisconsin
 * METX - Northeast Illinois Regional Commuter Railroad Corporation (Metra)
 * MF  - Middle Fork Railroad
 * MFCX - Farmers Coop Grain and Supply Company; First Union Rail
 * MFFX - M4 Holdings
 * MG  - Mobile and Gulf Railroad
 * MGA - Monongahela Railway; Norfolk Southern
 * MGGU - Marcevaggi
 * MGMX - J and J Partnership
 * MGRI - MG Rail
 * MGRS - Ferrocarriles Nacionales de Mexico
 * MGRX - M&G Resins USA, LLC
 * MGSX - Martin Gas Sales; CF Martin Sulphur
 * MH  - Mount Hood Railroad
 * MHAX - United States Department of the Interior (Bureau of Mines Helium Field Operations)
 * MHCO - Marquette and Huron Mountain Railroad
 * MHFX - MHF Logistical Solutions
 * MHLX - General American Transportation Corporation
 * MHM - Norfolk Southern
 * MHQU - Military Sealift Command (Washington, DC)
 * MHQZ - Military Sealift Command
 * MHRX - Mile-High Railcar Services
 * MHWA - Mohawk, Adirondack and Northern Railroad
 * MI  - Missouri-Illinois Railroad; Missouri Pacific Railroad; Union Pacific
 * MICO - Midland Continental Railroad
 * MID - Midway Railroad
 * MIDH - Middletown and Hummelstown Railroad
 * MIDL - Midland Railway
 * MIDX - MRC Rail Services
 * MIEU - MI Engineering
 * MIGN - Michigan Northern Railway
 * MILW - Milwaukee Road; Soo Line Railroad; Canadian Pacific Railway
 * MILX - Milchem; GE Rail Services Corporation
 * MILZ - Soo Line Railroad, Canadian Pacific Railway
 * MIMX - Minera Mexico International
 * MINE - Minneapolis Eastern Railway
 * MINU - China Ocean Shipping Company
 * MIPX - Millennium Petrochemicals
 * MIR - Minneapolis Industrial Railway
 * MIRX - Regional Recycling
 * MIS - Mississippi Central Railroad
 * MISS - Mississippian Railway
 * MISU - Malaysian International Shipping Corporation
 * MISX - Milwaukee Solvents and Chemicals Corporation
 * MJ  - Manufacturers' Junction Railway
 * MJRX - M Ryan Railway Service Contractors
 * MJVU - Merco
 * MKC - McKeesport Connecting Railroad
 * MKCX - Morrison-Knudsen
 * MKFX - Century Rail Enterprises
 * MKIX - M-K Railroad Equipment Leasing Company; Morrison-Knudsen
 * MKNR - Mackenzie Northern Railway
 * MKT - Missouri-Kansas-Texas Railroad; Union Pacific
 * MKTT - Missouri-Kansas-Texas Railroad; Union Pacific
 * MKTZ - Union Pacific
 * MLCU - NYK Line
 * MLCX - American Refrigerator Transit Company
 * MLD - Midland Railway Co. of Manitoba
 * MLEX - Miles
 * MLHX - American Refrigerator Transit Company
 * MLIX - Melbo Land and Investment Company
 * MLLX - Montell USA, Basell USA
 * MLMX - Morrison Grain Company; Metal Management
 * MLSX - Monsanto Company
 * MLUX - Solutia
 * MMA - Montreal, Maine & Atlantic Railway
 * MMAC - Montreal, Maine & Atlantic Railway
 * MMAX - Martin Marietta Aluminum; Martin Marietta Corporation
 * MMBX - Martin Marietta Corporation; Master Builders
 * MMCU - CIE Des Messageries Maritimes
 * MMCX - M&M Chemical Products; TransMatrix
 * MMID - Maryland Midland Railway
 * MMMU - Fesco Pacific Lines
 * MMMX - Minnesota Mining and Manufacturing (3M)
 * MMRR - Mid-Michigan Railroad
 * MMRX - Double M Ranch Enterprises
 * MMSX - Blue Circle
 * MMXZ - Murphy Motor Express
 * MNA - Missouri & Northern Arkansas Railroad
 * MNAX - C and S Directional Boring
 * MNBR - Meridian & Bigbee Railroad
 * MNC - Missouri North Central Railroad
 * MNCW - Metro-North Commuter Railroad
 * MNCX - Minnesota Corn Processors
 * MNJ - Middletown and New Jersey Railway
 * MNLU - Malaysian International Shipping Corporation
 * MNLX - Exxon-Mobil Corporation
 * MNN - Minnesota Northern Railroad
 * MNNR - Minnesota Commercial Railway
 * MNPX - Morton Norwich Products; Morton International
 * MNRX - Northstar Line
 * MNS - Minneapolis, Northfield and Southern Railway; Soo Line Railroad; Canadian Pacific Railway
 * MNTX - Minnesota Transportation Museum
 * MNWX - Minnesota Department of Public Service (Weights and Measures Division)
 * MOBX - Mobil Oil Corporation; Exxon-Mobil Corporation
 * MOC - Missouri Central Railroad
 * MOCX - Missouri Portland Cement Company
 * MOD - Missouri Pacific Railroad
 * MOEX - Morgan Engineering
 * MOFX - Maxton Oil and Fertilizer Company
 * MOGX - C.W. Brooks
 * MOHX - Monsanto Company; Solutia
 * MOLU - Mitsui OSK Lines
 * MOLX - International Molasses Corporation
 * MON - Monon Railroad; Seaboard System Railroad; CSX Transportation
 * MONX - Monsanto Company; Solutia
 * MOPZ - Flexi-Van Leasing
 * MORZ - Mitsui OSK Lines
 * MOSX - Mosinee Paper Corporation
 * MOSZ - Mitsui OSK Lines
 * MOT - Marine Oil Transportation
 * MOTC - Montreal Tramways
 * MOTU - Monsanto
 * MOTX - National Museum of Transportation
 * MOTZ - Mitsui OSK Lines
 * MOWX - Fortaleza Construction Company
 * MOXV - Moxahala Valley Railway
 * MP  - Missouri Pacific Railroad; Union Pacific
 * MPA - Maryland and Pennsylvania Railroad; York Railway
 * MPCX - Moyer Packing Company; Michels Pipeline Construction
 * MPEX - MotivePower
 * MPIT - Union Pacific
 * MPIX - Myer's Propane Gas Service; MotivePower
 * MPLI - Minnesota Prairie Line
 * MPLX - GE Rail Services
 * MPLZ - Union Pacific
 * MPRX - Motive Power & Equipment Solutions
 * MPSX - Missouri Public Service
 * MPTX - Procor
 * MPU - Missouri Pacific Railroad, Union Pacific
 * MPWX - Muscatine Power and Water
 * MPZ - Union Pacific
 * MQCX - Monarch Cement Company
 * MQGX - Morrison-Quirk Grain Corporation
 * MQPX - Millennium Inorganic Chemicals
 * MQRX - Macquarie Rail, Inc.; Wells Fargo Rail
 * MQT - Marquette Rail
 * MR  - McCloud River Railroad; McLeod Railway
 * MRAX - Mineral Range
 * MRCX - Evans Railcar Leasing Company; GE Rail Services Corporation
 * MRDX - MidAmerican Energy Company
 * MREX - Marshall Railway Equipment Corporation; Monad Railway Equipment Company
 * MRHS - Midland Railway
 * MRI - Mohall Railroad
 * MRIX - Motive Rail Industries
 * MRL - Montana Rail Link
 * MRMX - Midwest Railcar Corporation (previously named MRM Leasing and Management)
 * MRMZ - Monticello Railway Museum
 * MRR - Carolina Southern Railroad
 * MRRX - GE Rail Services; Murphy Road Recycling
 * MRS - Manufacturers Railway Company; Anheuser-Busch
 * MRSX - Mile-High Railcar Services
 * MS  - Michigan Shore Railroad
 * MSAZ - National Motor Freight Traffic Association
 * MSC - Illinois Central Gulf Railroad (Mississippi Central, Hattiesburg to Natchez)
 * MSCI - Mississippi Central Railroad (Oxford to Grand Jct)
 * MSCU - Mediterranean Shipping Company
 * MSCZ - Mediterranean Shipping Company
 * MSDR - Mississippi Delta Railroad, Rock Island Rail
 * MSDU - Mediterranean Shipping Company
 * MSE - Mississippi Export Railroad
 * MSEX - Princess Tours
 * MSIX - Morton International
 * MSKU - Maersk Line
 * MSL - Montgomery Short Line
 * MSLC - Minnesota Short Lines Company
 * MSMU - Mediterranean Shipping Company
 * MSMX - Mid South Milling Company
 * MSN - Meeker Southern Railroad
 * MSO - Michigan Southern Railroad
 * MSPX - P4 Productions
 * MSQU - Military Sealift Command (Bayonne, New Jersey)
 * MSR - Mississippi Southern Railroad (Watco)
 * MSRC - Kansas City Southern Railway (former MidSouth Railcorp)
 * MSRW - Mississippian Railway
 * MSTL - Minneapolis and St. Louis Railway; Chicago & North Western Railway; Union Pacific
 * MSTR - Massena Terminal Railroad
 * MSTX - Steam Railroading Institute
 * MSUU - USPCI
 * MSV - Mississippi and Skuna Valley Railroad
 * MSWY - Minnesota Southern Railway
 * MT  - Mississippi and Tennessee RailNet
 * MTAX - MTAX Corporation
 * MTC - Mystic Terminal Company
 * MTCO - Macon Terminal Company
 * MTCX - Mallard Transportation Company
 * MTCZ - Mayflower Transit and Storage
 * MTDX - Midwest Transportation and Development Company
 * MTFR - Minnesota Transfer Railway
 * MTIU - Welfit Oddy
 * MTIZ - American Marine Industries
 * MTLU - Montgomery Tank Lines
 * MTLX - Metal Link International
 * MTMU - March
 * MTMX - Modern Track Machinery
 * MTNX - Rocky Mountain Transportation Services
 * MTPX - Montana Power Company
 * MTR - Montour Railroad; Youngstown and Southeastern Railroad
 * MTRX - TransMatrix
 * MTSU - Marine Transport Service
 * MTTX - Trailer Train Company; TTX Company
 * MTW - Marinette, Tomahawk and Western Railroad
 * MTZ - Mitsui OSK Lines; Montgomery Tank
 * MTZX - Mitsui Rail Capital LLC
 * MULX - MUL Railcars Leasing LLC
 * MUSC - Memphis Union Station Company
 * MV  - Midland Valley Railroad
 * MVCX - Chaparral Energy
 * MVP - Missouri and Valley Park Railroad
 * MVRY - Mahoning Valley Railway
 * MVT - Mount Vernon Terminal
 * MWAX - Martin Marietta Materials
 * MWBX - Midwest By-Products Company
 * MWCL - Midwest Coal Handling
 * MWCX - Midwest Railcar Corporation
 * MWHX - Markwest Hydrocarbon Partners
 * MWLX - Midwest Locomotive Leasing and Sales
 * MWLZ - Madrigal-Wan Hai Lines Corporation
 * MWMX - Midwest Mud Company; Golden Leasing
 * MWPX - Murco Wall Products
 * MWR - Muncie and Western Railroad
 * MWRC - Mount Washington Railway
 * MWRL - Molalla Western Railway; Hillvista Investment Company
 * MWRR - Montana Western Railway
 * MWRX - Midwest Rail
 * MWSX - Midwest Solvents Company; GE Rail Services
 * MWTT - Michigan-Wisconsin Transportation Company
 * MXLU - Mexican Line
 * MZIZ - Marko B Zanovich