| (N&PB) Norfolk and Portsmouth Belt Line R.R. Co. | NPB | Apr-70 | |
| (North American Car Corp.) | PPKX | Apr-38 | |
| N.D.C. R.R. Co. | NDCR | 1/94-7/2000 | |
| N.I.K. Non-Stock Marketing Cooperative | NIKX | added 1/91; eliminated 7/93; 1/94-7/2000 | |
| N.I.K. Non-Stock Marketing Cooperative | CMTX | added 1/91; eliminated 1/93; 1/94 | |
| Naco Fertilizer Co. | NFX | 1/52; eliminated 4/55 | |
| Nalco Chemical Co. | NALX | added 7/59; 4/61-4/70; eliminated 1/75; added 10/84; eliminated 1/91 | |
| Namarib Co. | NLCX | 1/52; eliminated 4/57 | |
| NAMX Leasing Co. | NAMX | added 10/78; 1/80-7/2000 | |
| Napa Valley R.R. Co. | NVRR | added 1/88; 1/94-7/2000 | |
| Naparano Iron and Metal Co. | NIMX | added 1/78; 1/80; eliminated 10/81 | |
| Naparano/Railroad Division | NIMX | added 10/81; eliminated 4/84 | |
| Napierville Junction Ry. Co. | NJ | 1/75-1/80; eliminated 7/92 | |
| Nash County R.R. Corp. | NCYR | added 4/86; eliminated 4/93; 1/94-7/2000 | |
| Nashtex Leasing Inc. | NLTX | added 10/90 | |
| NTLX | 1/94-7/2000 | ||
| Nashville & Ashland City R.R. | NACR | added 1/82; eliminated 10/87; eliminated 7/89; 1/94-7/2000 | |
| Nashville and Eastern R.R. Corp. | NERR | added 1/87; 1/94-7/2000; eliminated 7/2001 | |
| Nashville Chattanooga & St. Louis Ry. | N&C | 4/38-4/61 | |
| NC | Jul-65 | ||
| Natchez Trace R.R. | NTR | added 4/82; 1/94; eliminated 4/94 | |
| National Aeronautics and Space Administration | NLAX | added 4/66; 10/66-4/70; eliminated 10/74; added 7/82; 1/94-7/2000 | |
| National Aluminate Corp. | NALX | Oct-57 | |
| National Aluminate Corp. -- Catalyst Division | NALX | eliminated 7/59 | |
| National Ammonia Co. | NAMX | added 7/78; eliminated 10/78 | |
| National Aniline Division, Allied Chemical & Dye Corp. | NANX | 1/52-10/57; eliminated 7/58 | |
| National Aniline Division, Allied Chemical Corp. | NANX | added 7/58; 4/61; eliminated 7/64 | |
| National Beef Packing Co. | NPCX | added 10/68; eliminated 7/69 | |
| National Bureau of Standards | NBS | Jan-80 | |
| National Car Co. | NX | Apr-38 | |
| NX | Oct-66 | ||
| NX | eliminated 1/72 | ||
| CPDX | eliminated 7/55 | ||
| EKSX | eliminated 1/68 | ||
| EMPX | eliminated 4/61 | ||
| FSX | Jan-52 | ||
| GEPX | added 7/55 | ||
| GEPX | eliminated 1/68 | ||
| GRSX | Jan-52 | ||
| JSSX | Jan-52 | ||
| LNPX | Jan-52 | ||
| LPVX | Jan-52 | ||
| MNX | 1/52; eliminated 7/56 | ||
| MNX | 10/57-4/70; eliminated 1/72 | ||
| OMX | Jan-52 | ||
| PPHX | Jan-52 | ||
| PPIX | eliminated 7/59 | ||
| RBNX | Jan-52 | ||
| RPHX | Jan-52 | ||
| SNX | 1/52-7/65 & 4/70; eliminated 7/70 | ||
| TICX | eliminated 1/72 | ||
| National Castings Division, Midland-Ross Corp. | NCEX | added 10/66; 10/66-4/70; eliminated 1/72 | |
| National Cylinder Gas Co. | NCYX | 10/57; eliminated 10/59 | |
| National Cylinder Gas, Division of Chemetron Corp. | NCYX | added 1/60; 4/61-1/75; eliminated 4/78 | |
| National Despatch Refrigerator Line (Chicago, New York & Boston Refrigerator Line) | NDRX | Apr-38 | |
| National Equipment Leasing Corp. | NDYX | added 7/69; 4/70-1/75 | |
| NELX | 7/65-1/75 | ||
| KOPX | added 4/62; 7/65-1/75; eliminated 4/75; 1/80 | ||
| National Fruit Product Co., Inc. | NFPX | 4/38-4/70; eliminated 1/73 | |
| National Lead Co. | NLFX | 7/65-10/66; eliminated 1/70 | |
| National Machinery Co. | NMCX | added 4/76; 1/80-1/94; eliminated 10/98; 7/2000 | |
| National Malleable and Steel Castings Co. -- temporary expiring 10Jan58 | NMSX | Oct-57 | |
| National Malleable and Steel Castings Co. -- temporary expiring 15Oct61 | NMSX | Apr-61 | |
| National Metal Corp. Ltd. | NMLX | added 1/93; eliminated 10/93; 1/94-7/2000 | |
| National Molasses Co. | NMLX | 4/38-1/75; eliminated 4/75 | |
| SSMX | 7/65-1/75; eliminated 4/75 | ||
| National Oil Co. | NOX | 4/38-10/57; eliminated 10/58 | |
| National Packing Co., Inc. | NPCX | added 7/67; eliminated 10/68 | |
| National R.R. Passenger Corp. NEC | AMTK | 1/80-7/2000 | |
| National Railway Equipment Co. | NREX | Jul-00 | |
| National Railway Historical Society (passenger cars) | NRHX | 1/94-7/2000 | |
| National Refrigerants, Inc. | NRIX | Jul-00 | |
| National Salvage and Service Corp. | NSSX | added 7/90; eliminated 7/92; 1/94-7/2000 | |
| National Silicates Ltd. | NSLX | 4/38-1/75; eliminated 7/78 | |
| National Starch & Chemical Co. | NLSX | added 7/96; 7/2000 | |
| National Starch & Chemical Co., d/b/a Specialty Synthetic Polymers Division | NLTX | added 10/99; 7/2000 | |
| National Steel Car Corp., Ltd. | NSCX | added 1/62; 7/65-1/80; eliminated 4/81 | |
| National Steel Car Ltd. | NSCX | added 4/81; 1/94-7/2000 | |
| National Steel Corp. | NSAX | 1/75-7/2000 | |
| National Sugar Refining Co. | NSRX | 10/57-1/80; eliminated 10/82 | |
| National Tank Car Co. | NTCX | Apr-38 | |
| National Tube Co. | NTX | Apr-38 | |
| National Wax Co. | NWAX | added 4/62; 7/65-1/94; eliminated 7/2000 | |
| National Zinc Co., Inc. | NZX | 4/38-1/80; eliminated 7/91 | |
| Nationwide Railroad Leasing, Inc. | IRCX | added 4/66; 10/66-4/70; eliminated 1/71 | |
| Natural Gas Co. | NGCX | Jan-52 | |
| Naugatuck Chemicals, Division of Dominion Rubber Co., Ltd. | NCX | 10/66; eliminated 4/67 | |
| Naugatuck R.R. Co., Inc. | NAUG | Jul-00 | |
| Navajo Express, Inc. | NAVE | Jul-00 | |
| Nealco-Monsanto Co. | NEAX | 4/38-1/52; eliminated 7/55 | |
| Nebkota Ry., Inc. | NRI | added 10/94; 7/2000 | |
| Nebraska Boiler Co. | NBCX | Jul-00 | |
| Nebraska Central R.R. Co. | NCRC | 1/94-7/2000 | |
| Nebraska Northeastern Ry. Co. | NENE | Jul-00 | |
| Nebraska Public Power District | NPPX | 1/80-7/2000 | |
| Nebraska, Kansas & Colorado RailNet, Inc. | NKCR | added 1/99; 7/2000 | |
| Needham Transportation Co. | LLKX | added 10/68; 4/70-1/80; eliminated 4/88 | |
| Nekoosa-Edwards Paper Co. | NEPX | Apr-38 | |
| Nelio Chemicals, Inc. | TRFX | Apr-61 | |
| Nemic Leasing Corp. | NEAX | 1/94-7/2000 | |
| NETX | 1/94-7/2000 | ||
| Nestle Brands FoodService Co., a Division of Nestle Food Co. | NESX | added 1/97; eliminated 10/97; 7/2000 | |
| Nevada Cement Co. | NVCX | added 7/95; eliminated 1/97; 7/2000 | |
| Nevada Copper Belt Ry. | NCB | Apr-38 | |
| Nevada Northern Ry. Co. | NN | 1/52-10/66 & 1/75-1/80; eliminated 1/88; added 10/94 | |
| Nevada Power Co. | NVPX | Jul-00 | |
| New Brunswick East Coast Ry. Co., Inc. | NBEC | Jul-00 | |
| New Brunswick Southern Ry. Co. Ltd. | NBSR | added 7/95; 7/2000 | |
| New England Central R.R., Inc. | NECR | added 7/95; 7/2000 | |
| New England Southern Rail Road Co. | NEGS | 1/94-7/2000; added 1/2001 | |
| New Hampshire and Vermont R.R. Co. | NHVT | added 7/90; 1/94; eliminated 1/2000; 7/2000 | |
| New Hampshire Central R.R., Inc. | NHCR | added 10/93; 1/94; eliminated 4/95; 7/2000 | |
| New Hampshire Northcoast Corp. | NHN | added 7/87; eliminated 1/92; 1/94-7/2000 | |
| New Haven Gas Light Co. | NHGX | Apr-38 | |
| New Hope & Ivyland R.R. Co. | NHIR | 1/75-1/80; eliminated 7/80 | |
| NHIR | added 10/89; eliminated 10/91 | ||
| New Hope & Ivyland R.R. Co., McHugh Brothers Heavy Hauling Inc. -- Operator & Lessee | NHIR | added 7/80; eliminated 10/89 | |
| New Hope & Ivyland Rail Road | NHRR | added 4/92; 1/94; eliminated 1/95; 7/2000; added 4/2001 | |
| New Hope & Ivyland Rail Road d/b/a Bucks County Railroad Preservation and Restoration Corp. | NHRR | added 10/91; eliminated 4/92 | |
| New Iberia & Northern R.R. Co. | NI&M | Apr-38 | |
| New Jersey Zinc Co. | NJZX | 4/38-4/70; eliminated 4/71 | |
| New Jersey, Indiana & Illinois R.R. Co. | NJII | 1/75-1/80; eliminated 5/83 | |
| New Orleans & Gulf Coast Ry. Co., Inc. | NOGC | Jul-00 | |
| New Orleans & Northeastern R.R. | N&NE | Jan-52 | |
| New Orleans and Lower Coast R.R. Co. | NLC | 1/52-10/66 & 1/75 | |
| New Orleans Lower Coast R.R., Inc. | NOLR | added 7/91; 1/94; eliminated 10/99; 7/2000 | |
| New Orleans Public Belt R.R. | NOPB | 1/75-7/2000 | |
| New Orleans Terminal | NOT | 1/75-7/2000 | |
| New Orleans, Texas & Mexico | NOTM | 1/75-1/80 | |
| New River & Pocahontas Consolidated Coal Co. | NRBX | 4/38-1/52 | |
| New York & Atlantic Ry. Co. | NYA | added 1/98; 7/2000 | |
| New York & Greenwood Lake Ry. | NYGL | Jul-00 | |
| New York & Lake Erie R.R. | NYLE | 1/94-7/2000 | |
| New York & Ogdensburg Ry. Co., Inc. | NYOG | added 1/99; 7/2000 | |
| New York Central Lines LLC | NYCX | Jul-00 | |
| New York Central R.R. Co. | NYC | 4/38-10/66 | |
| New York Central System | TOC | Oct-66 | |
| New York Connecting R.R. | NYCN | 1/75-1/80 | |
| New York Cross Harbor R.R. Terminal Corp. | NYCH | 1/94; eliminated 7/98; added 7/98; 7/2000 | |
| New York Despatch Refrigerator Line | NYDX | Jan-52 | |
| New York Despatch Refrigerator Line (Chicago, New York & Boston Refrigerator Co.) | NYDX | Apr-38 | |
| New York Dock Ry. | NYD | 1/75-1/80; eliminated 10/83 | |
| New York State Electric & Gas Corp. | NYSX | 10/57-1/80; eliminated 10/90; 1/94 | |
| New York, Chicago & St. Louis R.R. | NKP | 10/57-4/61 | |
| New York, Chicago & St. Louis R.R. (Nickel Plate Road) | NKP | 4/38-1/52 | |
| New York, Chicago & St. Louis R.R. (Norfolk and Western Ry. Co.) | NKP | 7/65-10/66 | |
| New York, New Haven & Hartford R.R. Co. | NH | 4/38-10/66 | |
| New York, Ontario & Western Ry. | OW | 4/38-1/52 | |
| New York, Susquehanna & Western R.R. | S&W | 4/38-10/57 | |
| New York, Susquehanna and Western R.R., Co. | NYSW | 1/52-10/66 & 1/75 | |
| New York, Susquehanna and Western R.R., Co. (Walter G. Scott, Trustee) | NYSW | 1/80; eliminated 1/81 | |
| New York, Susquehanna and Western Ry. Corp. | NYSW | added 4/81; 1/94; eliminated 4/96; 7/2000 | |
| DHDO | eliminated 7/91 | ||
| Newark Milk & Cream Co. | NMKX | Apr-38 | |
| Newaukum Valley R.R. Co. | NV | Apr-38 | |
| Newaygo Forest Products Ltd. | NFPX | 1/94-7/2000 | |
| Newburgh & South Shore R.R. Co. | NSR | added 7/87; 1/94-7/2000 | |
| Newburgh and South Shore Ry. Co. | NSS | 4/38-10/66 & 1/75-1/80; eliminated 7/86 | |
| Newcourt Capital U.S.A. Inc. | NCUX | added 10/97; 7/2000; eliminated 10/2000 | |
| Newport Division, Heyden Newport Chemical Corp. | NCOX | eliminated 7/65 | |
| Newport Division, Tenneco Chemicals, Inc. | NCOX | added 7/65; 7/65; eliminated 10/66 | |
| Newport Industries Co., a Division of Heyden Newport Chemical Corp. | NCOX | added 4/57; 10/57; eliminated 4/61 | |
| Newport Industries Division, Heyden Newport Chemical Corp. | NCOX | added 4/61; 4/61 | |
| Newport Industries, Inc. | NCOX | 4/38-1/52; eliminated 4/57 | |
| Newport News Shipbuilding and Dry Dock Co. | NNSX | 7/65-1/94; eliminated 7/96; added 10/96; eliminated 1/97; 7/2000 | |
| Newport Steel Corp. | NPTX | added 10/96; 7/2000 | |
| Newtex S.S. | NSC | 1/75-1/80 | |
| Nezperce R.R. Co. | NEZP | 1/75-1/80 | |
| Niagara Alkali Co. | NACX | 4/38-1/52; eliminated 7/56 | |
| Niagara Alkali Co. (Hooker Chemical Corp.) | NACX | Oct-66 | |
| Niagara Junction Ry. Co. | NIAJ | Jan-75 | |
| NJ | Apr-38 | ||
| Niagara Smelting Corp. | NSX | Apr-38 | |
| Niagara, St. Catharines & Toronto | NSCT | 1/75-1/80 | |
| Nichols Chemical Co., Ltd. | NLX | 4/38-4/61; eliminated 7/63 | |
| Nichols Chemical Co., Ltd. (Allied Chemical Canada, Ltd.) | NLX | Oct-66 | |
| Nicolet Badger Northern R.R., Inc. | NBNR | added 10/80; eliminated 1/89; 1/94; eliminated 4/95; 7/2000 | |
| Nimishillen & Tuscarawas L.L.C. | NTRY | added 4/2000; 7/2000 | |
| Nimishillen & Tuscarawas Ry. Co. | NTRY | added 4/90; 1/94; eliminated 4/2000 | |
| Nipak, Inc. | NKIX | added 4/66; 10/66-1/80; eliminated 10/80 | |
| Nitram Inc. | NITX | added 7/79; 1/80-1/94; eliminated 1/95; added 10/96; eliminated 1/97 | |
| Nitrogen Division, Allied Chemical & Dye Corp. | NDX | 10/57; eliminated 7/58 | |
| Nitrogen Division, Allied Chemical Corp. | NDX | added 7/58; 4/61 | |
| Nittany & Bald Eagle R.R. Co. | NBER | added 1/85; 1/94-7/2000 | |
| Nivco, Corp. | NIVX | added 1/67; 4/70-1/75; eliminated 7/75 | |
| NJ Transit Rail Operations | NJTR | 1/94-7/2000 | |
| NL Industries, Inc. | NLIX | 1/80; eliminated 5/83; 1/94 | |
| Nobles Rock R.R. | NRR | added 4/94; eliminated 7/97; added 1/2000; 7/2000 | |
| NORCHEM | NPCX | eliminated 1/86 | |
| CHEX | eliminated 1/86 | ||
| NORCHEM, Inc. | NARX | 1/94-7/2000 | |
| NPCX | added 1/86; eliminated 10/86 | ||
| CHEX | added 1/86; eliminated 10/86 | ||
| Nordic Warehouse, Inc. | NRDX | added 1/97; eliminated 7/98; 7/2000 | |
| Norfolk & Portsmouth Belt Line R.R. | N&PB | 4/38-10/66 | |
| Norfolk and Portsmouth Belt Line R.R. Co. | NPB | 1/75-7/2000 | |
| Norfolk and Western Railway Co. | ACY | added 1/77; 1/80; eliminated 1/91 | |
| Norfolk and Western Ry. | N&W | 1/52-10/66 | |
| NW | eliminated 1/91 | ||
| Norfolk and Western Ry. Co. | NFD | added 10/84 | |
| NJII | added 5/83 | ||
| NKP | 1/75-1/80; eliminated 1/91 | ||
| ITC | added 7/82; eliminated 1/91 | ||
| PW&V | Oct-66 | ||
| PWV | 1/75-1/80; eliminated 1/91 | ||
| VGN | 1/75-1/80; eliminated 1/91 | ||
| WAB | 1/75-1/80; eliminated 1/91 | ||
| Norfolk and Western Ry. Co. (N&W Dist.) | NW | 1/75-1/80 | |
| Norfolk Southern R.R. | NS | 4/38-10/66 | |
| Norfolk Southern R.R. Co. (Norfolk Southern) | CR | added 7/99; 7/2000 | |
| EL | added 7/99; 7/2000 | ||
| PRR | added 7/99; 7/2000 | ||
| RDG | added 7/99; 7/2000 | ||
| Norfolk Southern Ry. Co. | NKP | added 1/91; 1/94-7/2000 | |
| NS | 1/75-1/80 | ||
| NS | added 1/91; 1/94-7/2000 | ||
| NW | added 1/91; 1/94-7/2000 | ||
| CG | added 1/91; 1/94-7/2000 | ||
| CHW | added 1/91; 1/94-7/2000 | ||
| CRN | added 1/91; 1/94-7/2000 | ||
| GF | added 1/91; 1/94-7/2000 | ||
| INT | added 1/91; 1/94-7/2000 | ||
| ITC | added 1/91; 1/94-7/2000 | ||
| LHR | Jul-00 | ||
| PWV | added 1/91; 1/94-7/2000 | ||
| SA | added 1/91; 1/94-7/2000 | ||
| SOU | added 1/91; 1/94-7/2000 | ||
| TAG | added 1/91; 1/94-7/2000 | ||
| VGN | added 1/91; 1/94-7/2000 | ||
| WAB | added 1/91; 1/94-7/2000 | ||
| Norfolk Southern Ry. Co. (Norfolk Southern) | LV | Jul-00 | |
| MGA | Jul-00 | ||
| PAE | Jul-00 | ||
| PC | Jul-00 | ||
| Norfolk Southern Ry. Company | ACY | added 1/91; 1/94-7/2000 | |
| Norfolk Southern Transportation, Inc. | GA | Jan-94 | |
| Norfolk, Franklin & Danville Ry. Co. | AD | Jul-65 | |
| Norfolk, Franklin and Danville Ry. | AD | 4/70-1/75; eliminated 1/75; 1/80 | |
| Norfolk, Franklin and Danville Ry. Co. | NFD | 7/65-10/66 & 1/75-1/80 | |
| Norit Americas Inc. | ANCX | added 4/95; 7/2000 | |
| Normetal | NORM | 1/75-1/80 | |
| NorRail, Inc. | NRLX | 1/94; added 1/95; eliminated 10/99 | |
| FPFX | added 4/97; eliminated 10/99 | ||
| North American Car (Canada) Ltd. | NCCX | added 4/65; 7/65-1/75; eliminated 1/75 | |
| NCFX | added 7/63; 7/65-1/75 | ||
| NCHX | 7/65-1/75 | ||
| NCRX | added 7/66; 4/70-1/75 | ||
| NCTX | added 7/63; 7/65-1/75 | ||
| PTEX | added 1/75; 1/75 | ||
| North American Car Co. | QOCX | added 4/71; 1/75-1/80 | |
| North American Car Corp. | HLX | Apr-38 | |
| NADX | Apr-38 | ||
| NADX | Oct-66 | ||
| NAFX | added 1/59; 4/61-1/80 | ||
| NAHX | 1/52-1/80 | ||
| NATX | 1/52-1/80 | ||
| NCFX | Jan-80 | ||
| NCHX | Jan-80 | ||
| NCRX | Jan-80 | ||
| NCTX | Jan-80 | ||
| NGMX | added 7/59; 4/61-4/70; eliminated 11/73 | ||
| NIFX | 4/61-1/80 | ||
| NIGX | 7/65-1/75 | ||
| NIHX | 4/61-1/80 | ||
| NIRX | added 4/62; 7/65-1/80 | ||
| NISX | added 4/61; 4/61-1/75 | ||
| NJDX | 10/57-1/80 | ||
| NWMX | added 7/63; 7/65-10/66; eliminated 1/70 | ||
| NWRX | added 4/66; 10/66-4/70; eliminated 1/71 | ||
| NWX | Oct-57 | ||
| NWX | 7/65-1/80 | ||
| ABTX | added 4/66; 10/66-1/80 | ||
| ADMX | added 1/60; 4/61-1/75 | ||
| AESX | 1/52-1/80 | ||
| AGCX | added 7/60; 4/61-1/75; eliminated 4/75 | ||
| ALWX | added 10/70; 1/75-1/80 | ||
| AMPX | added 1/77; 1/80 | ||
| BBPX | added 4/65; 7/65-4/70; eliminated 7/73 | ||
| BCFX | added 1/74; 1/75-1/80 | ||
| BMDX | added 7/66; 10/66-1/80 | ||
| CFPX | added 10/72; 1/75-1/80 | ||
| COLX | added 1/66; 10/66-1/80; eliminated 7/82 | ||
| CRIX | 7/65-1/80 | ||
| CTCX | added 4/81 | ||
| DLRX | added 7/56; 10/57-1/80 | ||
| EHLX | Apr-70 | ||
| FSHX | added 10/74; 1/75-1/80 | ||
| GHMX | added 7/68; 4/70-1/75; eliminated 4/76 | ||
| HAMX | 7/65-1/75; eliminated 1/77 | ||
| HERX | 1/52-1/80 | ||
| HYGX | 1/52-7/65; eliminated 10/65 | ||
| ISTX | added 10/59; 4/61-1/80 | ||
| JWAX | 7/65-1/80 | ||
| LINX | added 4/66; 10/66-1/80 | ||
| LUNX | added 4/68; 4/70-1/80 | ||
| LVRX | 10/57-1/75; eliminated 4/75 | ||
| MARX | added 7/55; 10/57-4/70; eliminated 7/73 | ||
| MASX | added 4/68; 4/70-1/80 | ||
| MCAX | added 7/55; 10/57-1/75; eliminated 4/75 | ||
| MCLX | Oct-57 | ||
| MKGX | added 10/60; 4/61-1/75 | ||
| MMCX | 4/61-4/70; eliminated 1/72 | ||
| MORX | added 7/55; 10/57-1/75; eliminated 4/76 | ||
| MPLX | added 4/73; 1/75-1/80 | ||
| MRRX | added 7/55; 10/57-1/80 | ||
| MRX | added 7/55; 10/57-7/65; eliminated 10/66; 4/70-1/75 | ||
| MSCX | added 7/55; 10/57-1/75; eliminated 4/75 | ||
| MTX | added 7/55; eliminated 10/57; added 1/58; eliminated 7/59 | ||
| PBGX | added 7/64; 7/65-1/80; eliminated 7/82 | ||
| PTEX | Jan-80 | ||
| RAGX | Oct-57 | ||
| RCSX | added 7/60; 4/61-4/70; eliminated 10/74 | ||
| RPRX | added 7/55; eliminated 10/57; added 1/58; 4/61-1/80; eliminated 7/82 | ||
| SBCX | added 7/68; 4/70-1/75; eliminated 4/75 | ||
| SIMX | added 7/64; 7/65-4/70 | ||
| SUBX | added 4/65; 7/65-1/75; eliminated 1/77 | ||
| TNCX | added 7/65; 7/65-1/80 | ||
| TPFX | added 4/73; 1/75-1/80 | ||
| TRCX | added 7/56; 10/57-7/65; eliminated 10/65 | ||
| TRSX | added 4/81 | ||
| TTIX | added 4/65; 7/65-1/80 | ||
| UDAX | Jan-52 | ||
| USBX | added 7/82 | ||
| VENX | added 7/60; 4/61-1/80 | ||
| VOLX | added 7/67; 4/70-1/80 | ||
| WHSX | added 7/66; 10/66-1/80 | ||
| WMBX | 1/75; added 4/75; eliminated 7/76 | ||
| WPLX | added 1/67; 4/70-1/80 | ||
| North American Chemical | AJPX | added 4/94; 7/2000 | |
| DGHX | added 7/92; 1/94-7/2000 | ||
| North American Chemical Co. | NACX | added 4/91; eliminated 10/91 | |
| North American Cyanamid Ltd. | NCLX | 1/52-10/57; eliminated 7/58 | |
| North American Despatch (North American Car Corp.) | NADX | 1/52-7/65 | |
| NADX | 4/70-1/80 | ||
| North American Plastics, Inc. | NAPX | added 10/95; 7/2000 | |
| North American Rails Leasing Corp. | SEFX | added 1/99; 7/2000 | |
| North American Royalties, Inc. | NARX | added 1/78; 1/80; eliminated 10/82 | |
| North American Salt Co. | HCGX | added 1/95; 7/2000 | |
| North American Tank Line (North American Car Corp.) | NATX | Apr-38 | |
| North American Trading & Import Co. | NAMX | Apr-38 | |
| North AmericanãEmery Corp. | NAEX | added 10/59; 4/61 | |
| North Carolina & Virginia R.R. Co. | NCVA | added 1/88; 1/94-7/2000 | |
| North Carolina Ports Ry. Commission | NCPR | 1/94-7/2000 | |
| North Central Oklahoma Ry., Inc. | NCOK | added 4/82; eliminated 4/85 | |
| North Central Texas Ry., Inc. | NCTR | added 7/82; eliminated 1/83 | |
| North Country R.R. Corp. | NCRC | added 7/80; eliminated 1/82 | |
| North Louisiana & Gulf R.R. Co. | NL&G | added 11/73 | |
| NLG | 1/75-1/80; eliminated 1/88 | ||
| North Pacific Lumber Co. | NPLX | 1/80; eliminated 1/81 | |
| North Shore R.R. Co. | NSHR | added 1/85; 1/94-7/2000 | |
| North Star Oil Division of Shell Oil Co. of Canada, Ltd. | NSOX | added 1/62 | |
| North Star Oil, Ltd. | NSOX | 4/38-4/61; eliminated 1/62 | |
| North Star Steel Co. | NSTX | added 10/95; 7/2000 | |
| North Stratford R.R. Corp. | NSRC | added 7/79; 1/80; eliminated 4/88 | |
| North West Timber Co. | NWTX | Jan-94 | |
| North Western Refrigerator Line Co. | NWX | 4/38-1/52 | |
| MCLX | 4/38-1/52 | ||
| MCLX | eliminated 7/58 | ||
| RAGX | Jan-52 | ||
| RAGX | eliminated 7/58 | ||
| North Western Refrigerator Line Co., a Division North American Car Corp. | CRIX | eliminated 10/58 | |
| North Western Refrigerator Line Co., a Division of North American Car Corp. | NWX | eliminated 10/58 | |
| North Western Refrigerator Line Division North American Car Corp. | CRIX | added 10/58; 4/61 | |
| North Western Refrigerator Line, a Division of North American Car Corp. | NWX | added 10/58; 4/61 | |
| Northampton and Bath R.R. Co. | NB | 1/52-10/66 & 1/75; eliminated 4/79 | |
| Northbrook Corp. | CYDX | Jan-94 | |
| Northeast Corridor Foundation | NEFX | Jul-00 | |
| Northeast Illinois Regional Commuter R.R. Corp. |