# List of reporting marks: M

Note: Marks ending in U are for container owners; marks ending in X are not common carriers; marks ending in Z are for trailers without flanged wheels. All other marks are of common-carrier railroads.

## 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