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