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 MLRX - Maddie’s Locomotive Leasing & Resale 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 - Missouri Pacific;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 MSAX - Midwest Steel and Alloy 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