| NACR | Nashville & Ashland City R.R. | added 1/82; eliminated 10/87; eliminated 7/89; 1/94-7/2000 |
| NACX | Niagara Alkali Co. | 4/38-1/52; eliminated 7/56 |
| Hooker Chemical Corp. | added 7/56 | |
| Hooker Electrochemical Co. | 10/57; eliminated 10/58 | |
| Hooker Chemical Corp. | added 10/58; 4/61-7/65 | |
| Niagara Alkali Co. (Hooker Chemical Corp.) | Oct-66 | |
| Hooker Chemical Corp. | 4/70; eliminated 4/71 | |
| North American Chemical Co. | added 4/91; eliminated 10/91 | |
| General Electric Railcar Services Corp. | added 10/91; 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NADX | North American Car Corp. | Apr-38 |
| North American Despatch (North American Car Corp.) | 1/52-7/65 | |
| North American Car Corp. | Oct-66 | |
| North American Despatch (North American Car Corp.) | 4/70-1/80 | |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NAEX | North AmericanãEmery Corp. | added 10/59; 4/61 |
| NAFX | North American Car Corp. | added 1/59; 4/61-1/80 |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NAHX | North American Car Corp. | 1/52-1/80 |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NALX | National Aluminate Corp. | Oct-57 |
| National Aluminate Corp. -- Catalyst Division | eliminated 7/59 | |
| Nalco Chemical Co. | added 7/59; 4/61-4/70; eliminated 1/75; added 10/84; eliminated 1/91 | |
| NAMX | North American Trading & Import Co. | Apr-38 |
| Tank Car Corp. of America | Jan-52 | |
| National Ammonia Co. | added 7/78; eliminated 10/78 | |
| NAMX Leasing Co. | added 10/78; 1/80-7/2000 | |
| NANX | National Aniline Division, Allied Chemical & Dye Corp. | 1/52-10/57; eliminated 7/58 |
| National Aniline Division, Allied Chemical Corp. | added 7/58; 4/61; eliminated 7/64 | |
| NAP | The Narragansett Pier R.R. Co., Inc. | 1/75-1/80; eliminated 10/86; added 10/87; eliminated 7/89; 1/94-7/2000 |
| NAPX | North American Plastics, Inc. | added 10/95; 7/2000 |
| NAR | Northern Alberta Rys. Co. | 4/38-10/66 & 1/75-1/80; eliminated 4/81 |
| Canadian National Rys. | added 4/81; 1/94-7/2000 | |
| NARX | North American Royalties, Inc. | added 1/78; 1/80; eliminated 10/82 |
| NORCHEM, Inc. | 1/94-7/2000 | |
| NATX | North American Tank Line (North American Car Corp.) | Apr-38 |
| North American Car Corp. | 1/52-1/80 | |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NAUG | Naugatuck R.R. Co., Inc. | Jul-00 |
| NAVE | Navajo Express, Inc. | Jul-00 |
| NB | Northampton and Bath R.R. Co. | 1/52-10/66 & 1/75; eliminated 4/79 |
| Consolidated Rail Corp. | added 7/80; eliminated 7/99 | |
| NBCX | Nebraska Boiler Co. | Jul-00 |
| NBEC | New Brunswick East Coast Ry. Co., Inc. | Jul-00 |
| NBER | Nittany & Bald Eagle R.R. Co. | added 1/85; 1/94-7/2000 |
| NBIX | Bombardier Capital Rail, Inc. | added 10/99; 7/2000 |
| NBNR | Nicolet Badger Northern R.R., Inc. | added 10/80; eliminated 1/89; 1/94; eliminated 4/95; 7/2000 |
| NBS | National Bureau of Standards | Jan-80 |
| NBSR | New Brunswick Southern Ry. Co. Ltd. | added 7/95; 7/2000 |
| NBST | The New Braunfels & Servtex R.R., Inc. | eliminated 10/78 |
| N&C | Nashville Chattanooga & St. Louis Ry. | 4/38-4/61 |
| NC | Nashville Chattanooga & St. Louis Ry. | Jul-65 |
| Louisville and Nashville R.R. Co. (Nashville, Chattanooga & St. Louis) | 1/75-1/80 | |
| Louisville and Nashville R.R. Co. | eliminated 1/83 | |
| Seaboard System R.R., Inc. | added 1/83; eliminated 7/87 | |
| CSX Transportation, Inc. | added 7/87; 1/94-7/2000 | |
| NCAN | Incan Superior Ltd. | 1/75-1/80 |
| NCB | Nevada Copper Belt Ry. | Apr-38 |
| NCCX | North American Car (Canada) Ltd. | added 4/65; 7/65-1/75; eliminated 1/75 |
| NCEX | National Castings Division, Midland-Ross Corp. | added 10/66; 10/66-4/70; eliminated 1/72 |
| NCFX | North American Car (Canada) Ltd. | added 7/63; 7/65-1/75 |
| North American Car Corp. | Jan-80 | |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NCGX | Northern Refrigerator Line Inc. | 1/52-4/61 |
| Merchants Despatch Transportation Corp. | 7/65-10/66; eliminated 7/68 | |
| NCHX | North American Car (Canada) Ltd. | 7/65-1/75 |
| North American Car Corp. | Jan-80 | |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NCIX | Novacor Chemicals Inc. | added 4/96; eliminated 4/97 |
| Nova Chemicals Inc. | added 4/97; 7/2000 | |
| NCLX | North American Cyanamid Ltd. | 1/52-10/57; eliminated 7/58 |
| Nova Chemicals Ltd. | added 4/97; 7/2000 | |
| NCOK | North Central Oklahoma Ry., Inc. | added 4/82; eliminated 4/85 |
| NCOX | Newport Industries, Inc. | 4/38-1/52; eliminated 4/57 |
| Newport Industries Co., a Division of Heyden Newport Chemical Corp. | added 4/57; 10/57; eliminated 4/61 | |
| Newport Industries Division, Heyden Newport Chemical Corp. | added 4/61; 4/61 | |
| Newport Division, Heyden Newport Chemical Corp. | eliminated 7/65 | |
| Newport Division, Tenneco Chemicals, Inc. | added 7/65; 7/65; eliminated 10/66 | |
| NCPR | North Carolina Ports Ry. Commission | 1/94-7/2000 |
| NCRC | North Country R.R. Corp. | added 7/80; eliminated 1/82 |
| Nebraska Central R.R. Co. | 1/94-7/2000 | |
| NCRX | North American Car (Canada) Ltd. | added 7/66; 4/70-1/75 |
| North American Car Corp. | Jan-80 | |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NCRY | Northern Central Ry., Inc. | Jul-00 |
| NCSX | Merchants Despatch Transportation Corp. | 7/65-10/66; eliminated 7/67 |
| NOVA Chemicals (USA) Inc. | 7/2000; eliminated 7/2000 | |
| NCTR | North Central Texas Ry., Inc. | added 7/82; eliminated 1/83 |
| NCTX | North American Car (Canada) Ltd. | added 7/63; 7/65-1/75 |
| North American Car Corp. | Jan-80 | |
| PLM Railcar Management Services Canada Ltd. | eliminated 4/91 | |
| PLM International, Inc. | added 4/91; 1/94-7/2000 | |
| NCUX | Trinity Rail Management, Inc. | added 7/97; eliminated 10/97 |
| Newcourt Capital U.S.A. Inc. | added 10/97; 7/2000; eliminated 10/2000 | |
| Transport Capital | added 10/2000; eliminated 4/2001 | |
| Transport Capital Rail Partners, L.L.C. | added 4/2001 | |
| NCVA | North Carolina & Virginia R.R. Co. | added 1/88; 1/94-7/2000 |
| NCWX | Northwest Container Services, Inc. | Jul-00 |
| NCX | The Naugatuck Chemical Co. (United States Rubber Co.) | Apr-38 |
| Dominion Rubber Co., Ltd. | 1/52-7/65 | |
| Naugatuck Chemicals, Division of Dominion Rubber Co., Ltd. | 10/66; eliminated 4/67 | |
| UNIROYAL (1966) Ltd., Chemical Division | added 4/67; 4/70; eliminated 1/72 | |
| NCYR | Nash County R.R. Corp. | added 4/86; eliminated 4/93; 1/94-7/2000 |
| NCYX | National Cylinder Gas Co. | 10/57; eliminated 10/59 |
| National Cylinder Gas, Division of Chemetron Corp. | added 1/60; 4/61-1/75; eliminated 4/78 | |
| NDAX | Ouachita Fertilizer & Grain Co. | added 1/62; 7/65; eliminated 10/65 |
| NDCR | N.D.C. R.R. Co. | 1/94-7/2000 |
| NDIX | Merchants Despatch Transportation Corp. | added 7/56; 10/57; eliminated 7/60; 4/61 |
| NDM | Ferrocarriles Nacionales de Mexico (National Rys. of Mexico) | Jan-75 |
| Ferrocarriles Nacionales de Mexico (National Rys. of Mexico) (cars actually marked NdeM) | Jan-80 | |
| Ferrocarriles Nacionales de Mexico | 1/94-7/2000 | |
| NDRX | National Despatch Refrigerator Line (Chicago, New York & Boston Refrigerator Line) | Apr-38 |
| NDT | Ferrocarril Nacional de Tehuantepec (Tehuantepec National) | 1/75-1/80 |
| NDX | Nitrogen Division, Allied Chemical & Dye Corp. | 10/57; eliminated 7/58 |
| Nitrogen Division, Allied Chemical Corp. | added 7/58; 4/61 | |
| NDYX | National Equipment Leasing Corp. | added 7/69; 4/70-1/75 |
| Dresser Leasing Corp. | 1/80; eliminated 4/88 | |
| Sovran Leasing Corp. | added 4/88; eliminated 7/88 | |
| U.S. Rail Services, Inc. | added 7/88; 1/94; eliminated 4/94 | |
| USL Capital Rail Services | added 4/94; eliminated 10/96 | |
| First Union Rail | added 10/96; 7/2000 | |
| NEAX | Nealco-Monsanto Co. | 4/38-1/52; eliminated 7/55 |
| Nemic Leasing Corp. | 1/94-7/2000 | |
| NECR | New England Central R.R., Inc. | added 7/95; 7/2000 |
| NECX | Northeastern Central Railcar Leasing, Inc. | added 1/79; 1/80; eliminated 4/81 |
| Mid-Am Equipment, Inc. | added 7/81; 1/94-7/2000 | |
| NEFX | Northeast Corridor Foundation | Jul-00 |
| NEGS | New England Southern Rail Road Co. | 1/94-7/2000; added 1/2001 |
| NEKM | Northeast Kansas & Missouri Division, Mid-Michigan R.R., Inc. | added 7/90; 1/94; eliminated 7/99; 7/2000 |
| NELX | Northeastern Live Stock Express (Merchants Despatch Transportation Corp.) | Apr-38 |
| National Equipment Leasing Corp. | 7/65-1/75 | |
| Dresser Leasing Co. | 1/80; eliminated 7/86 | |
| NEMX | Ogden Martin Systems of Montgomery | added 10/96; 7/2000 |
| NENE | Nebraska Northeastern Ry. Co. | Jul-00 |
| NEO | Northeastern Oklahoma R.R. Co. | 1/52-10/66 |
| NEPX | Nekoosa-Edwards Paper Co. | Apr-38 |
| NERR | Nashville and Eastern R.R. Corp. | added 1/87; 1/94-7/2000; eliminated 7/2001 |
| NERX | Transportation Management Services, Inc. | added 4/97; eliminated 7/98; 7/2000 |
| NESX | Nestle Brands FoodService Co., a Division of Nestle Food Co. | added 1/97; eliminated 10/97; 7/2000 |
| NETX | Nemic Leasing Corp. | 1/94-7/2000 |
| NEVX | The Neville Co. | Jan-52 |
| NEZP | Nezperce R.R. Co. | 1/75-1/80 |
| NFD | Norfolk, Franklin and Danville Ry. Co. | 7/65-10/66 & 1/75-1/80 |
| Norfolk and Western Ry. Co. | added 10/84 | |
| NFPX | National Fruit Product Co., Inc. | 4/38-4/70; eliminated 1/73 |
| Newaygo Forest Products Ltd. | 1/94-7/2000 | |
| NFSX | Nuclear Fuel Services, Inc. | added 10/65; 10/66-1/75; eliminated 7/77 |
| NFVX | Gary Equipment Co. | eliminated 7/78 |
| NFX | Naco Fertilizer Co. | 1/52; eliminated 4/55 |
| NGCX | Natural Gas Co. | Jan-52 |
| NGIX | Northern Grain, Inc. | added 7/74; 1/75-1/80; eliminated 10/89; 1/94 |
| NGMX | North American Car Corp. | added 7/59; 4/61-4/70; eliminated 11/73 |
| NGRX | Georgia Building Authority (New Georgia R.R.) | Jan-94 |
| NGTX | Northern Gas Co., Inc. | added 7/64; 7/65-1/75 |
| NGTX | Vangas, Inc. | added 7/77; 1/80; eliminated 4/89 |
| Suburban Propane-Division of Quantum Chemical Corp. | 1/94; eliminated 4/97 | |
| Suburban Propane L.P. | added 4/97; 7/2000 | |
| NH | New York, New Haven & Hartford R.R. Co. | 4/38-10/66 |
| Penn Central Transportation Co. | Jan-75 | |
| Penn Central Transportation Co., Robert W. Blanchette, Richard C. Bond and John H. McArthur, Trustees | eliminated 4/76 | |
| Consolidated Rail Corp. | added 4/76; 1/80-1/94; eliminated 7/99 | |
| NHCR | New Hampshire Central R.R., Inc. | added 10/93; 1/94; eliminated 4/95; 7/2000 |
| NHGX | New Haven Gas Light Co. | Apr-38 |
| NHIR | New Hope & Ivyland R.R. Co. | 1/75-1/80; eliminated 7/80 |
| New Hope & Ivyland R.R. Co., McHugh Brothers Heavy Hauling Inc. -- Operator & Lessee | added 7/80; eliminated 10/89 | |
| New Hope & Ivyland R.R. Co. | added 10/89; eliminated 10/91 | |
| NHIX | Northern Refrigerator Line, Inc. | 1/52-4/61 |
| Merchants Despatch Transportation Corp. | 7/65; eliminated 7/66 | |
| NHN | New Hampshire Northcoast Corp. | added 7/87; eliminated 1/92; 1/94-7/2000 |
| NHRR | New Hope & Ivyland Rail Road d/b/a Bucks County Railroad Preservation and Restoration Corp. | added 10/91; eliminated 4/92 |
| New Hope & Ivyland Rail Road | added 4/92; 1/94; eliminated 1/95; 7/2000; added 4/2001 | |
| NHVT | New Hampshire and Vermont R.R. Co. | added 7/90; 1/94; eliminated 1/2000; 7/2000 |
| NIAJ | Niagara Junction Ry. Co. | Jan-75 |
| Consolidated Rail Corp. | Jan-80 | |
| NICD | Northern-Indiana Commuter Transportation District | 1/94-7/2000 |
| NIFX | North American Car Corp. | 4/61-1/80 |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NIGX | North American Car Corp. | 7/65-1/75 |
| NIHX | North American Car Corp. | 4/61-1/80 |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NIKX | N.I.K. Non-Stock Marketing Cooperative | added 1/91; eliminated 7/93; 1/94-7/2000 |
| NI&M | New Iberia & Northern R.R. Co. | Apr-38 |
| NIMX | Naparano Iron and Metal Co. | added 1/78; 1/80; eliminated 10/81 |
| Naparano/Railroad Division | added 10/81; eliminated 4/84 | |
| NIRX | North American Car Corp. | added 4/62; 7/65-1/80 |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NISX | North American Car Corp. | added 4/61; 4/61-1/75 |
| NITX | Nitram Inc. | added 7/79; 1/80-1/94; eliminated 1/95; added 10/96; eliminated 1/97 |
| NIVX | Nivco, Corp. | added 1/67; 4/70-1/75; eliminated 7/75 |
| NIWX | Northern Illinois & Wisconsin Ry. Corp. | Jul-00 |
| NJ | Niagara Junction Ry. Co. | Apr-38 |
| Napierville Junction Ry. Co. | 1/75-1/80; eliminated 7/92 | |
| CP Rail | added 7/92; 1/94; eliminated 7/94 | |
| Delaware and Hudson Ry. Co., Inc. | added 7/94; 7/2000 | |
| NJDX | North American Car Corp. | 10/57-1/80 |
| NJII | New Jersey, Indiana & Illinois R.R. Co. | 1/75-1/80; eliminated 5/83 |
| Norfolk and Western Ry. Co. | added 5/83 | |
| NJTR | NJ Transit Rail Operations | 1/94-7/2000 |
| NJZX | New Jersey Zinc Co. | 4/38-4/70; eliminated 4/71 |
| NKCR | Nebraska, Kansas & Colorado RailNet, Inc. | added 1/99; 7/2000 |
| NKIX | Nipak, Inc. | added 4/66; 10/66-1/80; eliminated 10/80 |
| NKP | New York, Chicago & St. Louis R.R. (Nickel Plate Road) | 4/38-1/52 |
| New York, Chicago & St. Louis R.R. | 10/57-4/61 | |
| New York, Chicago & St. Louis R.R. (Norfolk and Western Ry. Co.) | 7/65-10/66 | |
| Norfolk and Western Ry. Co. | 1/75-1/80; eliminated 1/91 | |
| Norfolk Southern Ry. Co. | added 1/91; 1/94-7/2000 | |
| NLAX | National Aeronautics and Space Administration | added 4/66; 10/66-4/70; eliminated 10/74; added 7/82; 1/94-7/2000 |
| NLC | New Orleans and Lower Coast R.R. Co. | 1/52-10/66 & 1/75 |
| Missouri Pacific System | eliminated 1/79 | |
| NLCX | Namarib Co. | 1/52; eliminated 4/57 |
| NLFX | National Lead Co. | 7/65-10/66; eliminated 1/70 |
| NL&G | North Louisiana & Gulf R.R. Co. | added 11/73 |
| NLG | North Louisiana & Gulf R.R. Co. | 1/75-1/80; eliminated 1/88 |
| MidLouisiana Rail Corp. | added 1/88; 1/94; eliminated 7/94 | |
| Kansas City Southern Ry. Co. | added 7/94; 7/2000 | |
| NLIX | NL Industries, Inc. | 1/80; eliminated 5/83; 1/94 |
| NLLX | Northern Line Layers Inc. | Jul-00 |
| NLPX | Perkins Motor Transport, Inc. | Jul-00 |
| NLSX | National Starch & Chemical Co. | added 7/96; 7/2000 |
| NLTX | Nashtex Leasing Inc. | added 10/90 |
| National Starch & Chemical Co., d/b/a Specialty Synthetic Polymers Division | added 10/99; 7/2000 | |
| NLX | Nichols Chemical Co., Ltd. | 4/38-4/61; eliminated 7/63 |
| Allied Chemical Canada, Ltd. | added 7/63; 7/65 | |
| Nichols Chemical Co., Ltd. (Allied Chemical Canada, Ltd.) | Oct-66 | |
| Allied Chemical Canada, Ltd. | 4/70-1/80; eliminated 5/83 | |
| Allied Chemical, a Division of Allied Canada, Inc. | added 5/83; eliminated 4/84 | |
| NMCX | Northern Refrigerator Line, Inc. | 10/57-4/61 |
| Merchants Despatch Transportation Corp. | 7/65-10/66; eliminated 4/67; 4/70 | |
| National Machinery Co. | added 4/76; 1/80-1/94; eliminated 10/98; 7/2000 | |
| NMKX | Newark Milk & Cream Co. | Apr-38 |
| NMLX | National Molasses Co. | 4/38-1/75; eliminated 4/75 |
| National Metal Corp. Ltd. | added 1/93; eliminated 10/93; 1/94-7/2000 | |
| NMMX | The National Machinery Co.--Michigan | Jul-00 |
| NMOR | Northern Missouri R.R. Co. | added 4/84; eliminated 4/86; eliminated 10/87 |
| NMSX | National Malleable and Steel Castings Co. -- temporary expiring 10Jan58 | Oct-57 |
| National Malleable and Steel Castings Co. -- temporary expiring 15Oct61 | Apr-61 | |
| NN | Nevada Northern Ry. Co. | 1/52-10/66 & 1/75-1/80; eliminated 1/88; added 10/94 |
| Northern Nevada R.R. Corp. | eliminated 7/98; 7/2000 | |
| N&NE | New Orleans & Northeastern R.R. | Jan-52 |
| NNSX | Newport News Shipbuilding and Dry Dock Co. | 7/65-1/94; eliminated 7/96; added 10/96; eliminated 1/97; 7/2000 |
| NODM | Mexico North Western | 1/75-1/80 |
| NOGC | New Orleans & Gulf Coast Ry. Co., Inc. | Jul-00 |
| NOKL | Northwestern Oklahoma R.R. Co. | 1/75; added 1/80; 1/80-7/2000 |
| NOLR | New Orleans Lower Coast R.R., Inc. | added 7/91; 1/94; eliminated 10/99; 7/2000 |
| NOLX | Northland Oil Co. (General American Transportation Corp.) | Apr-38 |
| NOPB | New Orleans Public Belt R.R. | 1/75-7/2000 |
| NOR | The Cincinnati Northern R.R. Co. | 23-Jul |
| Cincinnati Northern R.R. (Cleveland, Cincinnati, Chicago and St. Louis Ry.) | 4/38-1/52 | |
| NORM | Normetal | 1/75-1/80 |
| NORX | Northern Indiana Public Service Co. | added 1/65; 7/65-7/2000 |
| NOT | New Orleans Terminal | 1/75-7/2000 |
| NOTM | New Orleans, Texas & Mexico | 1/75-1/80 |
| NOW | Northern Ohio & Western Ry., Ltd. | added 10/95; eliminated 4/97; 7/2000 |
| NOX | National Oil Co. | 4/38-10/57; eliminated 10/58 |
| Arkansas Fuel Oil Corp. | added 10/58; 4/61; eliminated 1/62 | |
| Cities Service Oil Co. | added 1/62; eliminated 4/62 | |
| NP | Northern Pacific Ry. Co. | 1/52-10/66 |
| Burlington Northern Inc. | 1/75-1/80; eliminated 7/81 | |
| Burlington Northern R.R. Co. | added 7/81; 1/94 | |
| Burlington Northern Santa Fe Ry. Co. | Jul-00 | |
| N&PB | Norfolk & Portsmouth Belt Line R.R. | 4/38-10/66 |
| NPB | (N&PB) Norfolk and Portsmouth Belt Line R.R. Co. | Apr-70 |
| Norfolk and Portsmouth Belt Line R.R. Co. | 1/75-7/2000 | |
| NPCX | National Packing Co., Inc. | added 7/67; eliminated 10/68 |
| National Beef Packing Co. | added 10/68; eliminated 7/69 | |
| Northern Petrochemical Co. | added 1/75; 1/75-1/80 | |
| NORCHEM | eliminated 1/86 | |
| NORCHEM, Inc. | added 1/86; eliminated 10/86 | |
| Enron Chemical Co. | added 10/86; eliminated 4/87 | |
| USI Chemicals Co., Inc. | added 4/87 | |
| U.S. Industrial Chemicals Co., Division of National Distillers and Chemical Corp. | eliminated 7/87 | |
| USI Chemicals Co., Division of National Distillers & Chemical Corp. | added 7/87; eliminated 7/88 | |
| Quantum Chemical Corp., USI Division | added 7/88; 1/94; eliminated 4/98 | |
| Equistar Chemicals, LP | added 4/98; 7/2000 | |
| NPIX | Nuclear Packaging, Inc. | added 1/88; 1/94; eliminated 4/94 |
| VECTRA Technologies, Inc. | added 7/97; eliminated 4/98 | |
| Chem-Nuclear Systems, LLC | Jul-00 | |
| NPKX | The Nuckolls Packing Co. (General American Transportation Corp.) | Apr-38 |
| General American Transportation Corp. | 1/52-4/61 | |
| NPK-Tex, Inc. | added 7/80; eliminated 7/81 | |
| NPLX | North Pacific Lumber Co. | 1/80; eliminated 1/81 |
| NPM | Northern Pacific Ry. Co. | 4/61-10/66 |
| NPMX | Merchants Despatch Transportation Corp. | Oct-57 |
| NPPX | Nebraska Public Power District | 1/80-7/2000 |
| NPR | Northern Plains R.R., Inc. | Jul-00 |
| NPRB | Northern Pacific Ry. | 10/57-7/65 |
| NPRX | Yakima Interurban Lines Assn. | Jul-00 |
| NPT | Portland Terminal R.R. Co. (Ore.) | 1/75-7/2000 |
| NPTX | Newport Steel Corp. | added 10/96; 7/2000 |
| NRBX | New River & Pocahontas Consolidated Coal Co. | 4/38-1/52 |
| Northern Refrigerator Line | added 10/58; 4/61 | |
| Merchants Despatch Transportation Corp. | 7/65-1/94; eliminated 7/99 | |
| Fruit Growers Express Co. | added 7/99; 7/2000 | |
| NRC | Northern Refrigerator Line, Inc. | 4/38-4/61 |
| Merchants Despatch Transportation Corp. | 7/65-1/80; eliminated 1/83 | |
| NRCX | Northern Refrigerator Car Co. (Northern Refrigerator Line, Inc.) | Apr-38 |
| NRCX | Northern Rail Car Corp. | added 7/87; eliminated 7/91; 1/94-7/2000 |
| NRDX | Nordic Warehouse, Inc. | added 1/97; eliminated 7/98; 7/2000 |
| NREX | National Railway Equipment Co. | Jul-00 |
| NRHX | National Railway Historical Society (passenger cars) | 1/94-7/2000 |
| NRI | Nebkota Ry., Inc. | added 10/94; 7/2000 |
| NRIX | National Refrigerants, Inc. | Jul-00 |
| NRLX | NorRail, Inc. | 1/94; added 1/95; eliminated 10/99 |
| Bombardier Capital Rail, Inc. | added 10/99; 7/2000 | |
| NRMX | Northern Refrigerator Line, Inc. | 10/57-4/61 |
| NRNX | Keith Railway Equipment Co. | Jan-52 |
| NRPX | Northrop Corp. | added 4/90; 1/94; eliminated 7/94; 7/2000 |
| NRR | Nobles Rock R.R. | added 4/94; eliminated 7/97; added 1/2000; 7/2000 |
| NRT | Northern Refrigerator Line, Inc. | Apr-38 |
| NRTX | Northern Tank Car Lines (Northern Refrigerator Line, Inc.) | Apr-38 |
| NS | Norfolk Southern R.R. | 4/38-10/66 |
| Norfolk Southern Ry. Co. | 1/75-1/80 | |
| Southern Ry. System | eliminated 1/91 | |
| Norfolk Southern Ry. Co. | added 1/91; 1/94-7/2000 | |
| NSAX | National Steel Corp. | 1/75-7/2000 |
| NSC | Newtex S.S. | 1/75-1/80 |
| NSCT | Niagara, St. Catharines & Toronto | 1/75-1/80 |
| NSCX | National Steel Car Corp., Ltd. | added 1/62; 7/65-1/80; eliminated 4/81 |
| National Steel Car Ltd. | added 4/81; 1/94-7/2000 | |
| NSHR | North Shore R.R. Co. | added 1/85; 1/94-7/2000 |
| NSL | Norwood & St. Lawrence R.R. Co. | Jan-75 |
| Ogdensburg Bridge and Port Authority | added 1/77; eliminated 7/77 | |
| St. Lawrence R.R., Division of National Railway Utilization Corp. | added 7/77; 1/80; eliminated 1/86 | |
| St. Lawrence R.R. | added 1/86; eliminated 7/90 | |
| St. Lawrence & Raquette River R.R. | added 7/90; eliminated 1/94; 7/2000 | |
| NSLX | National Silicates Ltd. | 4/38-1/75; eliminated 7/78 |
| NSOX | North Star Oil, Ltd. | 4/38-4/61; eliminated 1/62 |
| North Star Oil Division of Shell Oil Co. of Canada, Ltd. | added 1/62 | |
| Shell Canada Ltd. | 7/65-4/70; eliminated 1/74 | |
| NSPX | Northern States Power Co. | added 7/90; 1/94-7/2000 |
| NSR | Newburgh & South Shore R.R. Co. | added 7/87; 1/94-7/2000 |
| NSRC | North Stratford R.R. Corp. | added 7/79; 1/80; eliminated 4/88 |
| NSRX | National Sugar Refining Co. | 10/57-1/80; eliminated 10/82 |
| NSS | Newburgh and South Shore Ry. Co. | 4/38-10/66 & 1/75-1/80; eliminated 7/86 |
| NSSX | National Salvage and Service Corp. | added 7/90; eliminated 7/92; 1/94-7/2000 |
| NSTX | North Star Steel Co. | added 10/95; 7/2000 |
| NSX | Niagara Smelting Corp. | Apr-38 |
| NTCX | National Tank Car Co. | Apr-38 |
| NTKX | VAE Nortrak North America, Inc. | added 1/99; 7/2000; eliminated 7/2001 |
| NTLX | Northern Tank Line Inc. | Jan-52 |
| Nashtex Leasing Inc. | 1/94-7/2000 | |
| NTR | Natchez Trace R.R. | added 4/82; 1/94; eliminated 4/94 |
| Mississippi Central R.R. Co. | added 4/94; 7/2000 | |
| NTRY | Nimishillen & Tuscarawas Ry. Co. | added 4/90; 1/94; eliminated 4/2000 |
| Nimishillen & Tuscarawas L.L.C. | added 4/2000; 7/2000 | |
| NTSX | Northeast Transportation Services, Co. | added 4/88 |
| Northeast Transportation Service, Inc. | 1/94; eliminated 10/96 | |
| NTTX | Trailer Train Co. | added 10/86; eliminated 1/92 |
| TTX Co. | added 1/92 | |
| TTX Co. (skeletonized, 5-unit, articulated, single-stack COFC car) | 1/94-7/2000 | |
| NTX | National Tube Co. | Apr-38 |
| NUCX | Nucor Steel Crawfordsville--Division of Nucor Corp. | added 4/97; eliminated 7/97; 7/2000 |
| NV | Newaukum Valley R.R. Co. | Apr-38 |
| NVCX | Nevada Cement Co. | added 7/95; eliminated 1/97; 7/2000 |
| NVPX | Nevada Power Co. | Jul-00 |
| NVR | Northern Vermont R.R. | added 4/97; 7/2000; eliminated 4/2001 |
| Bangor and Aroostook Rd. Co. | added 4/2001 | |
| NVRR | Napa Valley R.R. Co. | added 1/88; 1/94-7/2000 |
| N&W | Norfolk and Western Ry. | 1/52-10/66 |
| NW | Norfolk and Western Ry. Co. (N&W Dist.) | 1/75-1/80 |
| Norfolk and Western Ry. | eliminated 1/91 | |
| Norfolk Southern Ry. Co. | added 1/91; 1/94-7/2000 | |
| NWAX | National Wax Co. | added 4/62; 7/65-1/94; eliminated 7/2000 |
| Dussek Campbell, Inc. | added 7/2000; 7/2000 | |
| NWCX | Northwest Container Services, Inc. | added 4/98; 7/2000 |
| NWGX | Gorhams' Inc. | added 4/78; 1/80-1/94; eliminated 10/97; 7/2000 |
| NWMX | North American Car Corp. | added 7/63; 7/65-10/66; eliminated 1/70 |
| NWP | Northwestern Pacific R.R. Co. | 1/52-10/66 & 1/75-1/80; eliminated 1/93 |
| Southern Pacific Transportation Co. | Jan-94 | |
| Northwestern Pacific R.R. Co. | added 10/96; eliminated 4/97; 7/2000 | |
| NWRX | North American Car Corp. | added 4/66; 10/66-4/70; eliminated 1/71 |
| NWT | Northern Terminal | Jan-94 |
| NWTX | Northwestern Tank Line Co. | Apr-38 |
| North West Timber Co. | Jan-94 | |
| NorthWest Timber Co. | added 1/97; eliminated 7/97; 7/2000 | |
| NWX | North Western Refrigerator Line Co. | 4/38-1/52 |
| North American Car Corp. | Oct-57 | |
| North Western Refrigerator Line Co., a Division of North American Car Corp. | eliminated 10/58 | |
| North Western Refrigerator Line, a Division of North American Car Corp. | added 10/58; 4/61 | |
| North American Car Corp. | 7/65-1/80 | |
| General Electric Railcar Services Corp. | eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| NX | National Car Co. | Apr-38 |
| Fruit Growers Express Co. | 1/52-7/65 | |
| National Car Co. | Oct-66 | |
| Fruit Growers Express Co. | Apr-70 | |
| National Car Co. | eliminated 1/72 | |
| Fruit Growers Express Co. | added 1/72; 1/75-1/80; eliminated 4/82 | |
| NYA | New York & Atlantic Ry. Co. | added 1/98; 7/2000 |
| NYC | New York Central R.R. Co. | 4/38-10/66 |
| Penn Central Transportation Co. | Jan-75 | |
| Penn Central Transportation Co., Robert W. Blanchette, Richard C. Bond and John H. McArthur, Trustees | eliminated 4/76 | |
| Consolidated Rail Corp. | added 4/76; 1/80-1/94; eliminated 7/99 | |
| CSX Transportation | added 7/99; 7/2000 | |
| NYCH | New York Cross Harbor R.R. Terminal Corp. | 1/94; eliminated 7/98; added 7/98; 7/2000 |
| NYCN | New York Connecting R.R. | 1/75-1/80 |
| NYCX | New York Central Lines LLC | Jul-00 |
| NYD | New York Dock Ry. | 1/75-1/80; eliminated 10/83 |
| NYDX | New York Despatch Refrigerator Line (Chicago, New York & Boston Refrigerator Co.) | Apr-38 |
| New York Despatch Refrigerator Line | Jan-52 | |
| NYGL | New York & Greenwood Lake Ry. | Jul-00 |
| NYLB | The New York and Long Branch R.R. Co. | Jan-75 |
| Consolidated Rail Corp. | Jan-80 | |
| NYLE | New York & Lake Erie R.R. | 1/94-7/2000 |
| NYMX | Merchants Despatch Transportation Corp. | 10/57-1/75; eliminated 7/79 |
| NYOG | New York & Ogdensburg Ry. Co., Inc. | added 1/99; 7/2000 |
| NYRB | Merchants Despatch Transportation Corp. | added 1/58; eliminated 7/59 |
| NYRX | Merchants Despatch Transportation Corp. | added 1/59; 4/61-1/75; eliminated 7/79 |
| NYSW | New York, Susquehanna and Western R.R., Co. | 1/52-10/66 & 1/75 |
| New York, Susquehanna and Western R.R., Co. (Walter G. Scott, Trustee) | 1/80; eliminated 1/81 | |
| The New York, Susquehanna and Western Ry. Corp. | added 1/81; eliminated 4/81 | |
| New York, Susquehanna and Western Ry. Corp. | added 4/81; 1/94; eliminated 4/96; 7/2000 | |
| NYSX | New York State Electric & Gas Corp. | 10/57-1/80; eliminated 10/90; 1/94 |
| NZX | National Zinc Co., Inc. | 4/38-1/80; eliminated 7/91 |