| TACX | Transport Arts Corp. | added 4/72; 1/75-1/80; eliminated 4/88 |
| The American Coal Sales Co. | Jul-00 | |
| TADX | T.A.D. Jones & Co., Inc. | 4/38-1/52 |
| TAEA | Tangipahoa & Eastern | 1/75-1/80 |
| TAEX | The Andersons | added 10/2000 |
| TA&G | Tennessee, Alabama & Georgia Ry. Co. | 4/38-4/70 |
| TAG | Tennessee, Alabama & Georgia Ry. Co. | 1/75-1/80 |
| Southern Ry. System | eliminated 1/83; eliminated 1/91 | |
| Norfolk Southern Ry. Co. | added 1/91; 1/94-7/2000 | |
| TAGX | Texoma AG Products Inc. | Jul-00 |
| TAIX | Texas Alkyls, Inc. | added 4/90; eliminated 4/91; 1/94-7/2000 |
| TALX | Trical, Inc. | 1/94-7/2000 |
| TANX | Transitank Car Corp. | added 7/73; 1/75; eliminated 7/79 |
| Transitank Car Leasing Corp. | added 7/79; 1/80 | |
| Transitank Car Corp. | eliminated 10/93 | |
| TransiTech, Inc. | added 10/93; 1/94-7/2000; eliminated 10/2000 | |
| TAP | T and P Ry., Inc. | added 1/92; eliminated 7/93; 1/94 |
| TARX | Sandersville Leasing Co. | added 10/81 |
| Sandersville Leasing, Inc. | 1/94-7/2000 | |
| TAS | Tampa Southern R.R. Co. | 1/75-1/80 |
| TASD | Terminal Ry. Alabama State Docks | 1/75; added 7/77; 1/80-7/2000 |
| TASX | Tasco, Inc. | added 4/62; 7/65; eliminated 10/65 |
| Transammonia, Inc. | added 4/92; eliminated 7/94 | |
| Transrail, Inc. | 1/94; added 7/94; 7/2000 | |
| TATX | Tanco Transportation Corp. | added 7/79; 1/80; eliminated 4/89 |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| TA&W | Toledo, Angola & Western Ry. Co. | 4/38-4/70 |
| TAW | Toledo, Angola & Western Ry. Co. | 1/75-1/80; eliminated 1/80 |
| TAX | Trumbull Asphalt Co. | Apr-38 |
| TAZX | Trade Wind Ltd. | added 7/99; 7/2000 |
| TB | Twin Branch R.R. Co. | 1/75; eliminated 7/78 |
| TBAX | Toronto Pipe Line Co. | 1/52-10/57 |
| Canadian General Transit Co., Ltd. | 4/61; eliminated 4/61 | |
| TBCX | The Boeing Co. | added 1/68; 4/70-7/2000 |
| TBER | Terre Haute, Brazil & Eastern R.R. | added 4/88; eliminated 1/94; 7/2000 |
| TBRX | The Taylor Rail Group, Inc. | Jul-00 |
| TBRY | Thermal Belt Ry. | 1/94-7/2000 |
| TC | Tennessee Central Ry. Co. | 4/38-10/66 |
| TCB | Texas Central Business Lines Corp. | added 4/2001 |
| TCAX | Transportation Corp. of America | added 4/74; 1/75-1/80; eliminated 4/91 |
| Transportation Corp. of America | added 4/91; eliminated 1/94 | |
| General Electric Railcar Services Corp. | added 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| TCCX | Taylor Chemical Corp. | Apr-38 |
| Thompson Chemical Co. | 7/65; eliminated 4/66 | |
| Thompson Apex Co., Division of Continental Oil Co. | added 4/66; 10/66; eliminated 7/68 | |
| Trumix Concrete Co. | added 10/78; 1/80; eliminated 4/80 | |
| TCCX Corp. | added 4/80; eliminated 1/91; 1/94-7/2000 | |
| TCDX | Tank Car Despatchers Service, Inc. | 10/57; eliminated 1/58 |
| Tennessee Chemical Co. | added 1/83; eliminated 10/84 | |
| Union Tank Car Co. | added 10/84; 1/94-7/2000 | |
| TC&G | Tucson, Cornelia and Gila Bend R.R. Co. | Apr-38 |
| TCG | Tucson, Cornelia and Gila Bend R.R. Co. | 1/52-1/94; eliminated 10/97; 7/2000 |
| TCGX | Tri-County Gas, Inc. | added 10/83; 1/94; eliminated 7/96; added 10/96; eliminated 4/97 |
| Williams Energy Ventures, Inc. | added 10/99; 7/2000 | |
| TCIX | Tennessee Coal, Iron and Railroad Co. | 4/38-1/52 |
| Trinity Chemical Leasing, L.L.C. | added 4/2000; 7/2000; eliminated 10/2000 | |
| TCKR | Turtle Creek Industrial R.R., Inc. | added 1/83; 1/94-7/2000 |
| TCLX | Transit Co., Ltd. | 4/38-1/52; eliminated 10/53 |
| Union Tank Car Co. | added 10/53; 10/57 | |
| Trinity Chemical Leasing, L.L.C. | added 4/2000; 7/2000; eliminated 10/2000 | |
| TCMX | Transportation Corp. of America | added 4/89; eliminated 4/91 |
| Transportation Corp. of America | added 7/92; 1/94; eliminated 1/98 | |
| The CIT Group/Capital Finance, Inc. | added 1/98; 7/2000 | |
| TCOX | Trinity Cotton Oil Co. | Apr-38 |
| Trinity Cotton Oil Division of The Best Foods, Inc. | 1/52; eliminated 1/53 | |
| The Concrete Co. | Jul-00 | |
| TCPX | Taylor-Colquitt Co. | 1/52-10/57 |
| Transport Capital | added 10/2000; eliminated 4/2001 | |
| Transport Capital Rail Partners, L.L.C. | added 4/2001 | |
| TCQX | Thrall Car Manufacturing Co. | added 4/2000; 7/2000 |
| TCSX | Transcontinental Systems, Inc. | Apr-70 |
| Tank Car Services, Inc. | added 1/80; 1/80; eliminated 1/86 | |
| TCT | Texas City Terminal Ry. Co. | 4/38-7/2000 |
| TCTX | Tube City, Inc. | Jul-00 |
| TCWR | Twin Cities & Western R.R. | added 4/92; 1/94-7/2000 |
| TCWX | Charles Lennig & Co., Inc. | Apr-38 |
| TCX | The Texas Co. (Pennsylvania-Conley Tank Line, a Division of General American Transportation Corp.) | Apr-38 |
| General American Transportation Corp. | 1/52-7/65 | |
| Texaco, Inc. (General American Transportation Corp.) | Oct-66 | |
| General American Transportation Corp. | 4/70-1/94; eliminated 1/98 | |
| General American Marks Co. | added 1/98; 7/2000 | |
| TE | Tacoma Eastern Ry. Co. | added 4/95; eliminated 7/97; 7/2000 |
| TEAX | Teal Tank Car Co. | added 7/67; 4/70; eliminated 7/73 |
| Transportation Equipment, Inc. | added 7/93; 1/94-7/2000 | |
| TECX | TEC Terminals, Inc. | added 7/70 |
| Robertson Terminals, Inc. | 1/75; eliminated 1/77 | |
| Paktank Gulfcoast, Inc. | added 1/77 | |
| Texas Crushed Stone Co. | added 10/82; eliminated 5/83; 1/94 | |
| TEGX | Transenergy Grinding Inc. | added 4/97; 7/2000 |
| TEIX | Transportation Equipment, Inc. | added 4/84; 1/94-7/2000 |
| TELX | Tacoma Electrochemical Co. (Pennsylvania Salt Mfg. Co. of Washington) | 4/38-1/52 |
| Pennsylvania Salt Manufacturing Co. of Washington | eliminated 10/57 | |
| Pennsalt of Washington Division, Pennsalt Chemicals Corp. | added 10/57; 10/57; eliminated 10/60 | |
| Pennsalt Chemicals Corp. | added 10/60; 4/61-10/66; eliminated 1/69 | |
| Pennsalt Carriers Corp. | added 1/69; 4/70; eliminated 1/75 | |
| Pennwalt Carriers Corp. | added 1/75; 1/75-1/80; eliminated 1/93 | |
| ELF Atochem North America, Inc. | added 1/93; 1/94-7/2000 | |
| TEM | Temiskaming & Northern Ontario Ry. | Apr-38 |
| Ontario Northland Ry. | 1/52-4/70 | |
| Temiskaming & Northern Ontario Ry. | 1/75-1/80 | |
| TEMX | Temple-Eastex Inc. | added 10/78; 1/80; eliminated 7/89 |
| Temple-Inland Forest Products Corp. | added 7/89; 1/94-7/2000 | |
| TENN | Tennessee Ry. Co. | 1/75-7/2000 |
| TENX | Tennessee Corp. | Jan-52 |
| TETX | Transelectrix Technology Inc. | added 10/87; eliminated 7/90 |
| Asea Brown Boveri, Inc. | added 7/90; eliminated 7/92 | |
| TEXC | Texas Central R.R. Co. | 4/70-1/80; eliminated 7/92; 1/94-7/2000 |
| TFM | TFM, S.A. de C.V. | added 10/97; 7/2000 |
| TFVM | Terminal Ferroviaria Del Valle De Mexico, S.A. de C.V. | Jul-00 |
| T&G | Tremont & Gulf Ry. | 4/38-4/70 |
| TGAX | Texasgulf Inc., Agricultural Chemicals Operation | added 1/78; 1/80; eliminated 10/80 |
| Texasgulf Inc. | added 10/80; 1/94; eliminated 10/95 | |
| PCS Phosphate Co., Inc. | added 10/95; 7/2000 | |
| TGBX | T.G. Bright & Co., Ltd. | Apr-38 |
| TGCX | Tank Gas Corp. | 1/52-4/61; eliminated 7/63 |
| Thru-Haul, Inc. | added 7/63; eliminated 1/65 | |
| Hopane Distributing Co. | added 1/65; 7/65-10/66; eliminated 10/68 | |
| Protane Corp., Division of Northern Gas Co. | added 10/68 | |
| Protane Corp., Division of Northern Propane Gas Co. | 4/70; eliminated 10/74; 1/75-1/80 | |
| The GEON Co. | added 7/99; 7/2000; eliminated 1/2001 | |
| The PolyOne Co. | added 1/2001 | |
| TGIX | Texas Gulf, Inc. | added 10/72 |
| Texasgulf Inc. | 1/75; eliminated 1/78 | |
| Texasgulf Inc., Sulphur Operation | added 1/78; 1/80; eliminated 10/80 | |
| Texasgulf Inc. | 1/94; eliminated 10/95 | |
| PCS Phosphate Co., Inc. | added 10/95; 7/2000 | |
| TGOX | Transgo | added 4/65; eliminated 7/65 |
| Transgo, Inc. | added 7/65; 7/65-10/66; eliminated 4/69 | |
| Railease Corp. | added 4/69; eliminated 1/70 | |
| Rail-U.S. Leasing, Inc. | added 1/70; 4/70-1/75; eliminated 4/78 | |
| U.S. Rail Services, Inc. | added 4/78; 1/80-1/94; eliminated 4/94 | |
| USL Capital Rail Services | added 4/94; eliminated 10/96 | |
| First Union Rail | added 10/96; 7/2000 | |
| TGPX | Tamak Gas Products Co., Inc. | added 4/62 |
| Tamak Transportation Corp. | 7/65-7/2000 | |
| TGRX | Transglobal Rail, Inc. | Jul-00 |
| TGSX | Texas Gulf Sulphur Co. | 7/65-4/70 |
| Texasgulf Inc. | 1/75; eliminated 1/78 | |
| Texasgulf Inc., Soda Ash Operation | added 1/78; 1/80-1/94; eliminated 10/95 | |
| TG Soda Ash, Inc. | added 10/95; eliminated 4/2000 | |
| FMC Corp. | added 4/2000; 7/2000 | |
| TGX | Texas Gulf Sulphur Co. | Apr-38 |
| THB | Toronto, Hamilton & Buffalo Ry. Co. | 4/38-1/80; eliminated 10/87 |
| CP Rail | Jan-94 | |
| CP Rail System | eliminated 1/97 | |
| Canadian Pacific Ry. Co. | added 1/97; 7/2000 | |
| THCX | Publiker Industries, Inc. | added 1/86; 1/94; eliminated 10/94 |
| MG Industries | Jul-00 | |
| THKX | Thompson-Hayward Chemical Co. | 4/38-10/66; eliminated 4/70 |
| THRX | Transportation Corp. of America | added 7/99; 7/2000 |
| THX | The Harbauer Co. | Apr-38 |
| TIBR | TimberRock R.R. Co., Inc. | Jul-00 |
| TICX | Fruit Growers Express | Jul-65 |
| Thermice Corp., Philadelphia, PA (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; eliminated 1/75 | |
| TIDX | Tidewater Oil Co. | 4/38-10/66; eliminated 10/67 |
| Getty Oil Co. | added 10/67; 4/70; eliminated 4/72 | |
| TIIX | Transportex International, Inc. | added 10/74; 1/75; eliminated 4/79 |
| TILX | Trinity Industries Leasing Co. | added 7/79; 1/80-7/2000 |
| TIMX | Trinity Industries Leasing Co. | added 1/81; 1/94-7/2000 |
| TINX | Trinity Industries Leasing Co. | added 1/99; 7/2000 |
| TIOC | Tioga Central R.R. Co. | added 4/87; eliminated 7/92 |
| TIPP | Tippecanoe R.R. Co. | added 4/80; eliminated 7/90 |
| TIRL | Tonawanda Island R.R., Inc. | added 7/84; eliminated 10/91; 1/94-7/2000 |
| TISH | Tishomingo R.R. Co., Inc. | added 4/2000; 7/2000 |
| TISX | Trinity Industries Leasing Co. | added 1/99; 7/2000 |
| TJRX | Shirley M. Brooks | added 1/86; eliminated 4/86 |
| TJRX | S.M. Brooks | added 4/86; 1/94-7/2000 |
| TK | Tuskegee R.R. | 10/57-4/61 |
| TKCX | Thiele Kaolin Co. | added 4/68; 4/70-7/2000 |
| TKEN | Tennken R.R. Co., Inc. | added 4/84; 1/94-7/2000 |
| TKX | Thomas Keery Co., Inc. | Apr-38 |
| TLCX | Trinidad Leaseholds (Canada) Ltd. | Jan-52 |
| Transport Leasing Co. | added 10/59; 4/61 | |
| Transport Leasing, a Division of Pullman Inc. | 7/65-4/70; eliminated 10/70 | |
| Pullman Transport Leasing Co., a Subsidiary of Pullman Inc. | added 10/70; 1/75 | |
| Pullman Leasing Co., a Subsidiary of Pullman Inc. | 1/80; eliminated 4/81 | |
| Pullman Leasing Co. | added 4/81; eliminated 1/90 | |
| Itel Rail Corp. | added 1/90; eliminated 10/92 | |
| General Electric Railcar Services Corp. | added 10/92; 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| TLDX | Transport Leasing, a Division of Pullman Inc. | 7/65-4/70; eliminated 10/70 |
| Pullman Transport Leasing Co., a Subsidiary of Pullman Inc. | added 10/70; 1/75 | |
| Pullman Leasing Co., a Subsidiary of Pullman Inc. | 1/80; eliminated 4/81 | |
| Pullman Leasing Co. | added 4/81; eliminated 1/90 | |
| Itel Rail Corp. | added 1/90; eliminated 10/92 | |
| General Electric Railcar Services Corp. | added 10/92; 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| TLLX | Trinity Industries Leasing Co. | added 4/2000; 7/2000 |
| TLSX | Tank Line Service, Inc. | 1/52-4/61; eliminated 1/62 |
| TLTX | Tilcon Tomasso Quarries Inc. | added 7/87; 1/94-7/2000 |
| TM | The Texas Mexican Ry. Co. | 1/52-7/2000 |
| TMAX | Tennessee River Pulp & Paper Co. | added 7/75; 1/80; eliminated 10/91 |
| Packaging Corp. of America | added 10/91; 1/94; eliminated 7/98 | |
| Tenneco Packaging Inc. | added 7/98 | |
| Tenneco Packaging Co. | Jul-00 | |
| TMBL | Tacoma Municipal Belt Line Ry. | 1/75-7/2000 |
| TMC | Temiscouata Ry. | Apr-38 |
| TMCX | The Mars Co. | Apr-38 |
| The Maxson Corp. | 1/75; eliminated 1/78 | |
| Temco Corp. | added 10/84; 1/94; eliminated 10/96 | |
| TMEX | Trinity Industries Leasing Co. | added 1/99; 7/2000 |
| TMGX | Transporte Multimodal de Granos | 1/94-7/2000 |
| TMIX | TransMatrix, Inc. | added 4/89; 1/94-7/2000 |
| TMLX | Temco Corp. | added 1/88; 1/94; eliminated 10/96; 7/2000 |
| TMOX | Textiles Monterrey, S.A. | Jan-52 |
| TMPX | Texas Municipal Power Agency | added 1/82; eliminated 5/83; added 10/83; 1/94; eliminated 10/96; 7/2000 |
| TMRX | Peter Kiewitt Sons' Co. | 1/80; eliminated 7/81 |
| TMSS | Towanda-Monroeton Shippers Lifeline, Inc. | 1/80-7/2000 |
| TMSX | Thomas Maddock's Sons Pottery (Standard Sanitary Mfg. Co.) | Apr-38 |
| TMT | Trailer Marine Transportation Corp. | 1/80-7/2000 |
| TMX | Mars Inc. | Apr-38 |
| Union Refrigerator Transit Lines, a Division of the General American Transportation Corp. | 1/52-10/66 | |
| Union Refrigerator Transit Lines | eliminated 7/67 | |
| TN | Texas & Northern Ry. Co. | 1/52-1/94; eliminated 1/99; 7/2000 |
| TNAX | TransAmerican Refining Corp. | added 7/90; 1/94; eliminated 1/2000; eliminated 4/2000; 7/2000 |
| TNCX | North American Car Corp. | added 7/65; 7/65-1/80 |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| TNER | Texas Northeastern Division, Mid-Michigan R.R., Inc. | added 1/91; 1/94-7/2000 |
| TNGX | Texas Natural Gasoline Corp. | 1/52-10/57; eliminated 7/60 |
| Union Texas Natural Gas Corp. | added 7/60; 4/61 | |
| Union Texas Petroleum, a Division of Allied Chemical Corp. | eliminated 7/64 | |
| TNM | Texas-New Mexico Ry. Co. | Jan-75 |
| Missouri Pacific R.R. Co. | Jan-80 | |
| Missouri Pacific System | eliminated 7/84; eliminated 1/90 | |
| Union Pacific R.R. Co. | added 7/90; 1/94-7/2000 | |
| TNMR | Texas & New Mexico Division, Austin & Northwestern R.R. Co., Inc. | added 1/90; 1/94-7/2000 |
| T&NO | Texas & New Orleans R.R. | 4/38-4/61 |
| TNO | Texas & New Orleans R.R. | 10/57-4/61 |
| T&NO | Southern Pacific Co. (Texas and Louisiana Lines) | Jul-65 |
| T&NO | Texas and New Orleans R.R. Co. (Southern Pacific Co.) | Oct-66 |
| TNR | TennRail Corp. | added 4/92; 1/94; eliminated 7/94 |
| Kansas City Southern Ry. Co. | added 7/94; 7/2000 | |
| TOC | New York Central System | Oct-66 |
| Penn Central Transportation Co. | 4/70-1/75 | |
| 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; eliminated 1/83; added 5/83; eliminated 7/99; 1/94 | |
| TOCX | True's Oil Co. | 4/38-10/57; eliminated 7/58 |
| TOE | Texas, Oklahoma & Eastern R.R. Co. | 1/75-7/2000 |
| TOLX | Petrolite Corp., Ltd., Tretolite Co. Division | Jan-52 |
| The TXL Oil Corp. | added 1/62 | |
| Texaco Inc. | eliminated 7/63 | |
| TOR | Trans-Ontario Ry. Co. | added 4/97; eliminated 7/98 |
| TOR | RailLink Canada Ltd. | Jul-00 |
| TORX | Toronto Elevators Ltd. | 10/57-4/61 |
| Maple Leaf Mills Ltd. | 7/65-1/75; eliminated 7/77 | |
| TOTX | Cotco, Inc. | added 4/97; 7/2000 |
| TOV | Tooele Valley Ry. Co. | 1/75-1/80; eliminated 1/82 |
| TOVX | Tovrea Packing Co. (Mather Stock Car Co.) | Apr-38 |
| TOZX | Eureka Springs Water Co. | Apr-38 |
| Ozarka Co. | Apr-61 | |
| Ozarka Water Co., Inc. | 7/65-10/66; eliminated 4/67 | |
| Ozarka Water Co. | added 4/67; 4/70 | |
| T&P | Texas & Pacific Ry. | 4/38-4/70 |
| TP | Texas & Pacific Ry. Co. | 10/57-1/75; eliminated 1/77 |
| Missouri Pacific R.R. Co. | Jan-80 | |
| Missouri Pacific System | added 1/77; 1/94; eliminated 4/97 | |
| Union Pacific R.R. Co. | added 4/97; 7/2000 | |
| TPAX | Trans Pacific Leasing Inc. | added 1/70; 4/70-1/75; eliminated 7/76 |
| TPBX | General American Transportation Corp. | added 4/70; 1/75-1/80; eliminated 10/92 |
| TPCX | Colgate-Palmolive-Peet Co. | 4/38-1/52; eliminated 1/53 |
| TPCX | The Purdy Co. | 1/75-1/80; eliminated 1/90 |
| TPDX | Tennessee Products Corp. | Apr-38 |
| Tennessee Products & Chemical Corp. | 1/52; eliminated 4/57 | |
| Union Tank Car Co. | added 4/57; 10/57-4/70; eliminated 7/73 | |
| TPEX | General Electric Railcar Services Corp. | 1/94-7/2000 |
| TPFX | North American Car Corp. | added 4/73; 1/75-1/80 |
| General Electric Railcar Services Corp. | 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| TPGX | Technical Propellants, Inc. | added 10/90; 1/94-7/2000 |
| TPHX | Thomas Payne Holdings Inc. | Jul-00 |
| TPIX | Tropicana Products Sales, Inc. | 4/70; added 7/70; 1/75-7/2000; eliminated 4/2001 |
| Tropicana Transportation Corp. | added 4/2001 | |
| TPL | Texas and Pacific Ry. Co. | 1/75; eliminated 1/77 |
| Missouri Pacific R.R. Co. | added 1/77; 1/80 | |
| Missouri Pacific System | eliminated 1/81 | |
| TPLX | Pacific Lumber Co. | 1/52; eliminated 7/55 |
| American Refrigerator Transit Co. | 7/65-4/70; eliminated 10/74; 1/75-1/80 | |
| TPMP | Texas Pacific-Missouri Pacific Terminal R.R. of New Orleans | 1/75; eliminated 4/78 |
| TPPX | Thilmany Pulp & Paper Co. | added 7/74; 1/75-1/80; eliminated 4/86 |
| Thilmany Pulp & Paper Co. (captive service) | Jan-94 | |
| TPRX | Texas Power & Light Co. | 1/52-10/57; eliminated 1/58; added 7/80; 1/94 |
| TPSX | TPS Leasing Co., LLC | Jul-00 |
| TPT | Trenton-Princeton Traction Co. | Jan-75 |
| Consolidated Rail Corp. | Jan-80 | |
| TPTX | Trailer Train Co. | added 10/80; eliminated 4/81 |
| Trailer Train Co. | 1/94-7/2000 | |
| TP&W | Toledo, Peoria & Western R.R. | 4/38-4/70 |
| TPW | Toledo, Peoria & Western Ry. Co. | 1/75-1/80 |
| The Atchison, Topeka and Santa Fe Ry. Co. | eliminated 7/88 | |
| Toledo, Peoria & Western Ry. Co. | added 7/89; eliminated 4/91 | |
| Toledo, Peoria & Western Ry. Corp. | added 4/91; eliminated 10/92; 1/94; added 4/95; 7/2000 | |
| TPX | Trojan Powder Co. | 4/38-1/52 |
| Trojan Powder Co., care of Pennsylvania Trojan Powder Co. | Oct-57 | |
| Trojan Powder Co. | eliminated 7/58 | |
| TQEX | U.S. Rail Services | added 7/89; 1/94; eliminated 4/94 |
| USL Capital Rail Services | added 4/94; eliminated 10/96 | |
| First Union Rail | added 10/96; 7/2000 | |
| TR | Tomahawk Ry., Ltd. Partnership | added 4/92; eliminated 7/93; 1/94; eliminated 10/97; 7/2000; added 10/2000 |
| TRAX | American Refrigerator Transit Co. | added 4/54; 10/57-4/70; eliminated 7/70 |
| Railtex Corp. | added 7/78 | |
| Railtex Inc. | Jan-80 | |
| Railtex Corp. | Jan-94 | |
| Railtex Inc. | Jul-00 | |
| TRC | Trona Ry. Co. | 1/52-1/80; eliminated 1/85; 1/94-7/2000 |
| TRCX | Texas Refining Co. | Apr-38 |
| North American Car Corp. | added 7/56; 10/57-7/65; eliminated 10/65 | |
| Treco Sales, Inc. | 1/80; eliminated 1/92 | |
| Tri-County Commuter Rail Authority | Jul-00 | |
| TREX | Tetra Technologies, Inc. | added 1/90; 1/94; eliminated 4/2000; 7/2000 |
| TRFX | Tiona Refining Co. | Apr-38 |
| Turpentine & Rosin Factors, Inc. | 1/52-10/57 | |
| Nelio Chemicals, Inc. | Apr-61 | |
| TRGX | Terminal Grain Corp. | added 7/74; 1/75-1/80; eliminated 7/93 |
| Upper Merion and Plymouth Leasing Co. | added 7/93; 1/94; eliminated 4/96 | |
| First Union Rail | added 4/96; 7/2000 | |
| TRIN | Trinidad Ry., Inc. | 1/94-7/2000 |
| TRIX | Iowa Public Service Co. | added 7/75; 1/80 |
| Midwest Power Systems | added 1/94; eliminated 4/96 | |
| MidAmerican Energy Co. | added 4/96; eliminated 4/99 | |
| GATX Captial Corp. | added 4/99; 7/2000 | |
| TRLX | Texas Railcar Leasing Co. | added 7/89; 1/94-7/2000 |
| TRMW | City of Tacoma, d/b/a Tacoma Rail Mountain Division | Jul-00 |
| TRMX | The Railroad Museum--TRM Industries | 1/75; added 4/75; 1/80; eliminated 1/92; added 4/92; 1/94-7/2000; eliminated 1/2001; added 4/2001 |
| TRNX | Trinity Railcar Leasing Corp. | added 7/79; 1/80; 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 | |
| TRPX | Tropigas Inc. of Florida | added 1/66; 10/66-1/80; eliminated 1/89 |
| Petrolane Gas Service Ltd. Partnership | 1/94; eliminated 10/95 | |
| AmeriGas Propane, L.P. | added 10/95; eliminated 4/98; 7/2000 | |
| TRRA | Terminal R.R. Association of St. Louis | 4/38-7/2000 |
| TRSX | Transrail Systems, Inc. | added 10/69; 4/70; eliminated 4/72 |
| California Tank Car Line, Inc. | added 4/72; 1/75-1/80; eliminated 4/81 | |
| North American Car Corp. | added 4/81 | |
| General Electric Railcar Services Corp. | eliminated 1/86 | |
| Endasa, S.A. de C.V. | eliminated 4/89; 1/94 | |
| TRTX | W.J. Kirberger, Trustee | added 10/80; 1/94; eliminated 7/94; 7/2000 |
| TRUX | Midwest Bottle Gas Co. | added 1/78; 1/80-7/2000 |
| TRYX | Tri-County Cooperative Association | added 1/81; eliminated 7/88 |
| TS | Tidewater Southern Ry. Co. | 10/57-1/80; eliminated 10/87 |
| Union Pacific R.R. Co. | added 10/87; eliminated 4/88 | |
| TSBY | Tuscola and Saginaw Bay Ry. Co., Inc. | added 1/78; 1/80-7/2000 |
| TSCX | The Steel Company of Canada, Ltd. | 4/38-10/66; eliminated 10/69 |
| TSE | Texas South-Eastern Ry. Co. | 1/75; added 4/79; 1/80-7/2000 |
| TSNR | Tyson R.R., Inc. | 1/94-7/2000 |
| TSO | Tidewater Southern Ry. | 4/38-1/52 |
| TSPX | Texas Sulphur Products Co., Inc. | eliminated 4/79 |
| Texas Sulphur Products Co. | added 4/79; 1/80 | |
| TSRD | Twin State R.R. Co. | added 10/88; 1/94-7/2000 |
| TSRR | Tennessee Southern R.R. Co., Inc. | added 7/88; 1/94; eliminated 7/95; 7/2000 |
| TSSX | U.S. Dept. of Energy, Albuquerque Operations Office | added 10/84; 1/94; eliminated 10/97; 7/2000 |
| TSU | Tulsa-Sapulpa Union Ry. Co. | 1/75-1/94; eliminated 7/96 |
| Tulsa-Sapulpa Union Ry. Co., L.L.C. | added 7/96; 7/2000 | |
| TSUX | Tri-State Utility Inc. | Jan-94 |
| TSVX | Transerv Systems, Inc. | added 10/69; 4/70 |
| Tennsv, Inc. | 1/94-7/2000 | |
| TSWR | Toppenish, Simcoe & Western R.R. | added 10/93; 1/94; eliminated 4/95; 7/2000 |
| TSX | Tank Specializing Co. | 1/52-4/61 |
| TSXX | Tri-State Generation & Transmission Association, Inc. | 1/94; added 1/97; eliminated 10/98; 7/2000 |
| TT | Toledo Terminal R.R. Co. |