| R | Rutland Ry. | 4/38-4/70 |
| RACN | Raccoon River R.R. Co. | added 7/81; eliminated 4/82 |
| RACX | Railway Accessories Co. (J.L. Ortner) | 1/52-7/65 |
| Railway Accessories Co. | 10/66; eliminated 10/67 | |
| General Electric Railcar Services Corp. | added 10/95; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| RAGX | North Western Refrigerator Line Co. | Jan-52 |
| North American Car Corp. | Oct-57 | |
| North Western Refrigerator Line Co. | eliminated 7/58 | |
| RAHX | Rohm and Haas Co. | 4/38-1/75; eliminated 7/78; added 4/90; 1/94; added 7/94; 7/2000 |
| RAIX | United States Leasing International, Inc. | added 7/70; 1/75-1/80; eliminated 10/81 |
| Union Carbide Corp., Chemicals and Plastics Division | added 10/81; eliminated 5/83 | |
| Union Carbide Corp. | added 5/83; eliminated 1/93 | |
| Union Carbide Chemicals and Plastics Co., Inc. | added 1/93; 1/94; eliminated 1/95; eliminated 4/95 | |
| Union Carbide Corp. | added 1/95; added 4/95; 7/2000 | |
| RAMX | Railway Automated Machinery Co. | added 7/67; 4/70; eliminated 1/71 |
| Rail America, Ltd. | added 7/82; 1/94 | |
| RAOX | Roberts & Oake, Inc. (General American Transportation Corp.) | Apr-38 |
| General American Transportation Corp. | 1/52-4/61 | |
| RAPX | Rapco Transportation Co. | added 10/81; 1/94; eliminated 4/2000; 7/2000 |
| RARW | Rarus Ry. Co. | 1/94-7/2000 |
| RASX | C.A. Rasmussen | Jul-00 |
| RATX | RailTex Service Co., Inc. | Jul-00 |
| RAWX | Riverside Acid Works | Apr-38 |
| Riverside Acid & Inhibitor Co. | Jan-52 | |
| Platte River Power Authority | added 4/84; eliminated 4/90; 1/94-7/2000 | |
| RAX | RPI-AAR Cooperative Test Program | 1/75-7/2000 |
| RAYX | Peck Iron & Metal Co., Inc. | 7/65-10/66; eliminated 10/67 |
| RBBN | Burlington Northern R.R. Co. | added 4/75 |
| Burlington Northern Inc. | 1/80; eliminated 7/81 | |
| Burlington Northern R.R. Co. | added 7/81; 1/94 | |
| RBBQ | Chicago, Burlington and Quincy R.R., Co. | 7/65-10/66 |
| Chicago, Burlington and Quincy R.R. (Burlington Northern) | Apr-70 | |
| Burlington Northern Inc. | 1/75-1/80; eliminated 7/81 | |
| Burlington Northern R.R. Co. | added 7/81; 1/94 | |
| RBBX | Burlington Refrigerator Express Co. | added 4/57; 10/57-4/70; eliminated 10/70 |
| Western Fruit Express Co. | added 10/70; 1/75-1/80; eliminated 4/80; 1/94 | |
| Ringling Bros. and Barnum & Bailey | Jul-00 | |
| RBCS | Colorado & Southern Ry. Co. | 4/61-4/70 |
| The Colorado and Southern Ry. Co. | 1/75-1/80; eliminated 4/82 | |
| Burlington Northern R.R. Co. | added 4/82; 1/94 | |
| RBCX | The Rail-Bridge Corp. | added 10/90; 1/94-7/2000 |
| RBKX | Red Bank R.R. Co. | Jan-94 |
| RBLX | Brent C. Lewis | Jul-00 |
| RBMN | Reading Blue Mountain & Northern R.R. Co. | 1/94; added 4/2000; 7/2000; eliminated 7/2000 |
| RBNX | National Car Co. | Jan-52 |
| Fruit Growers Express Co. | 10/57-1/80; eliminated 10/89; 1/94 | |
| RBOX | American Rail Box Car Co. | added 10/74; 1/75; eliminated 7/79 |
| Railbox Co. | added 7/79; 1/80-1/94; eliminated 4/2000 | |
| TTX Co. | added 4/2000; 7/2000 | |
| RBW | Burlington Northern Inc. | 1/80; eliminated 7/81 |
| Burlington Northern R.R. Co. | added 7/81 | |
| Burlington Northern Express Co. | Jan-94 | |
| Burlington Northern R.R. Co. | eliminated 4/95 | |
| RBWX | Western Fruit Express Co. | 10/57-1/80; eliminated 1/81 |
| RC | Rosslyn Connecting R.R. Co. | 1/75-1/80 |
| RCCX | Relco Tank Line | added 4/69; eliminated 7/69 |
| Relco Leasing Corp. | added 7/69; 4/70; eliminated 4/72 | |
| Relco Tank Line, Inc. | added 4/72; 1/75 | |
| Relco Tank Line Division of Relco Nevada Corp. | 1/80; eliminated 10/86 | |
| Relco Tank Line, Inc. | added 10/86; eliminated 7/87 | |
| RCKX | Refiners Car Corp. | Apr-38 |
| RCMX | Ringgold Coal Mining Co. | Jan-80 |
| Railroad Car Management Co., Inc. | added 4/85; eliminated 1/94 | |
| Services Unlimited | added 1/94; eliminated 4/2000; 7/2000 | |
| RCOX | Arco Products Co., Division of Atlantic Richfield Co. | added 10/91; 1/94 |
| Arco Products Co. | eliminated 7/2000 | |
| Amoco Oil Co. | added 7/2000; 7/2000 | |
| RCPX | Railcar, Ltd. | added 7/97; 7/2000; eliminated 10/2000 |
| Southern Illinois Railcar Co. | added 10/2000 | |
| RCRR | Red Coat Road & Rail Ltd. | Jul-00 |
| RCRX | Reagent Chemical & Research, Inc. | added 11/73; 1/75-7/2000 |
| RCSX | Railway Tank Car Service, Inc. | 1/52-10/57; eliminated 7/60 |
| North American Car Corp. | added 7/60; 4/61-4/70; eliminated 10/74 | |
| Railroad Car Service Corp. | added 4/85; eliminated 1/87 | |
| RCWX | Royster Chemical Works | Apr-38 |
| F.S. Royster Guano Co. | 1/52-10/57 | |
| Royster Chemical Works | eliminated 10/59 | |
| F.S. Royster Guano Co. | added 10/59; 4/61-10/66; eliminated 10/68 | |
| Royster Co. | added 10/68; 4/70-1/75 | |
| RDCX | Regional Disposal Co. | Jul-00 |
| RDG | Reading Co. | 4/38-1/75 |
| Reading Co., Andrew L. Lewis, Jr. and Joseph L. Castle, Trustees | eliminated 4/76 | |
| Consolidated Rail Corp. | added 4/76; 1/80-1/94; eliminated 7/99 | |
| Norfolk Southern R.R. Co. (Norfolk Southern) | added 7/99; 7/2000 | |
| RDIX | Rapid Industrial Plastics Co. | added 1/85; 1/94-7/2000 |
| RECX | Central Louisiana Electric Co., Inc. | added 4/81; 1/94-7/2000 |
| REDX | Miron/U.S.A. Ltd. | added 1/86; eliminated 7/91; 1/94-7/2000 |
| RELX | Relco Leasing Corp. | added 7/69; 4/70; eliminated 1/72 |
| Relco Tank Line, Inc. | added 1/72; 1/75 | |
| Relco Tank Line Division of Relco Nevada Corp. | 1/80; eliminated 10/86 | |
| Relco Tank Line, Inc. | added 10/86; 1/94-7/2000 | |
| REMX | R.E.M.X. Corp. | added 1/80; 1/80; eliminated 5/83 |
| REPX | Mid-West Despatch Car Co. | Apr-38 |
| Reliable Packing Co. | 10/57-4/61 | |
| RESX | Rescar Inc. | added 1/78; 1/80; eliminated 5/83; 1/94-7/2000 |
| REX | Railway Express Agency, Inc. | 1/52-4/70 |
| REA Express, Inc. | eliminated 4/74 | |
| RFCX | Rentco Division, Fruehauf Corp. | added 4/67; 4/70 |
| R&F Coal Co. | added 7/80; eliminated 7/91 | |
| RFMX | Robert F. Miller | added 1/74; 1/75-1/80 |
| Caldwell-Baker Co. | eliminated 10/90; 1/94-7/2000 | |
| RFP | Richmond, Fredricksburg & Potomac R.R. Co. | 4/38-1/80; eliminated 1/92 |
| Richmond, Fredricksburg & Potomac Ry. Co. | added 1/92; eliminated 7/92 | |
| CSX Transportation, Inc. | 1/94-7/2000 | |
| RFPX | Republic Food Products Co. (Merchants Despatch Transportation Corp.) | Apr-38 |
| RFRX | Rick Franklin Corp. | Jul-00 |
| RGCX | Riverside Gas Co. | added 1/65; 7/65; eliminated 10/66 |
| Rio Grande Chemical Sales Co. | added 4/79; 1/80-7/2000 | |
| RGEX | Royal Gorge Industries, LLC | Jul-00 |
| RGHX | Ring's Gas & Appliance Co. | added 4/73; 1/75; eliminated 4/79 |
| RGIX | Republic Gas and Utilities Corp. | added 10/74; 1/75-7/2000; eliminated 4/2001 |
| RGLX | Roberto de la Garza y Hnos, S.A. | eliminated 1/83 |
| RGOX | Richfield Oil Co. of California (Richfield Oil Corp.) | Apr-38 |
| RGPX | Royal Gas Products Corp. | Apr-61 |
| RGRX | Rio Grande Railcar Co., Inc. | 1/94-7/2000 |
| RGTX | Residco | 1/94-7/2000 |
| R&GV | Ray & Gila Valley R.R. | 4/38-1/52 |
| RHAX | Sulphur Sales, Inc. | added 10/74; 1/75-1/80; eliminated 1/86 |
| RHBX | R.H. Bogle Co. | 1/52-1/80; eliminated 5/83 |
| RHRX | Rahr Malting Co. | added 4/90; 1/94; eliminated 7/99; 7/2000 |
| RI | Choctaw, Oklahoma & Gulf R.R. (Chicago, Rock Island & Pacific Ry.) | 23-Jul |
| Chicago, Rock Island & Pacific Ry. | 23-Jul | |
| Des Moines, Iowa Falls & Northern R.R. (Chicago, Rock Island & Pacific Ry.) | 23-Jul | |
| Rock Island (Chicago, Rock Island & Pacific Ry. Co.) | 4/38-1/80; eliminated 7/80 | |
| RICX | Rustless Iron Corp. of America | 1/52-4/61 |
| Rockwell International Corp. | 1/94-7/2000 | |
| RIG | Chicago, Rock Island & Mexico R.R. (Chicago, Rock Island & Gulf Ry.) | 23-Jul |
| Chicago, Rock Island & Texas R.R. (Chicago, Rock Island & Gulf Ry.) | 23-Jul | |
| Chicago, Rock Island & Gulf Ry. | 7/23-1/52 | |
| RIIX | Reilly Industries, Inc. | added 4/2000; 7/2000 |
| RILX | Interail, Inc. | added 7/80; 1/94; eliminated 7/96 |
| Garvey International, Inc. | added 7/96 | |
| Garvey International, Inc., Garvey Grain Division | Jul-00 | |
| RIMX | Ready Mixed Concrete Co. | 1/94-7/2000 |
| RIPX | Rochester Independent Packer, Inc. | added 7/69; 4/70-1/80; eliminated 5/83; 1/94 |
| RIRX | Rock Island Refining Co. (Duncan Oil Co., Inc.) | Apr-38 |
| RIS | Rock Island Southern Ry. | 4/38-1/52 |
| RJAX | R.J. Allison Co. | Jan-52 |
| RJBX | R.J. Brown Co. | Jan-52 |
| RJCL | R.J. Corman R.R. Co./Cleveland Line | added 10/91; 1/94-7/2000 |
| RJCM | R.J. Corman R.R. Co./Memphis Line | added 1/90; eliminated 7/91 |
| R.J. Corman R.R. Co./Memphis Line | added 10/91; 1/94-7/2000 | |
| RJCN | R.J. Corman R.R. Co./Allentown Lines, Inc. | added 10/96; 7/2000 |
| RJCP | R.J. Corman R.R. Co./Pennsylvania Lines, Inc. | added 10/96; 7/2000 |
| RJCR | R.J. Corman R.R. Corp. | added 4/87; 1/94-7/2000; eliminated 1/2001 |
| R.J. Corman R.R. Corp./Bardstown Line | added 1/2001 | |
| RJCW | R.J. Corman R.R. Co./Western Ohio Line | 1/94; added 4/94; 7/2000 |
| RJCX | Andy Equipment Inc. | Jan-75 |
| RJNX | Bogle Industries | added 7/81; eliminated 10/82 |
| The R.H. Bogle Co. | eliminated 4/88 | |
| RJRX | R.J. Roesling & Co. | 1/52-4/61 |
| Shippers' Car Line, Division of ACF Industries, Inc. | 7/65-1/75; eliminated 7/78 | |
| Shippers' Car Line Division, ACF Industries Inc. | added 10/78; 1/80; eliminated 4/88 | |
| ACF Industries, Inc. | added 4/88; 1/94; eliminated 7/97; 7/2000 | |
| RKCX | Knox Kershaw Co., Inc. | added 1/69; 4/70-1/80; eliminated 4/85; 1/94-7/2000 |
| RKG | Rockingham R.R. Co. | 4/38-10/66 |
| RKMW | Chicago, Rock Island and Pacific R.R. Co. | Jan-80 |
| RL | Rutland Line, Inc. | Jul-00 |
| RLEX | Republic Locomotives, Inc. | Jul-00 |
| RLGN | RaiLink Canada Ltd, d/b/a RaiLink Mackenzie Northern | added 7/98; 7/2000 |
| RLGX | Roberto de la Garza y Hnos, S.A. | 10/57-1/80 |
| RLHH | RaiLink Canada Ltd, d/b/a RaiLink Southern Ontario | added 7/98; 7/2000 |
| RLIX | Rail Link Inc. | Jul-00 |
| RLK | RaiLink Canada Ltd, d/b/a RaiLink Ottawa Valley | added 7/98; 7/2000 |
| RLKX | Delta Tank Line Co. | eliminated 4/84 |
| RLKX | R.L. and S.S. Klein | added 4/84; eliminated 4/85 |
| RLMX | The David J. Joseph Co. | added 1/90; 1/94; eliminated 4/2000 |
| Joseph Transportation Inc. | added 4/2000; 7/2000 | |
| RLSX | Robert L. Shipp | added 10/83; eliminated 1/90 |
| RLTX | Randolph L. Johnston | Jul-00 |
| RMAX | American Refrigerator Transit Co. | 10/57-4/70; eliminated 4/74; 1/75-1/80 |
| Rocky Mountain Rail Society | Jul-00 | |
| RMBX | American Refrigerator Transit Co. | 7/65-4/70; eliminated 4/72 |
| RMCX | Reid, Murdoch & Co. | Apr-38 |
| Reade Manufacturing Co., Inc. | added 7/55; 10/57-4/61 | |
| Reynolds Metals Co. | added 4/69; 4/70-7/2000 | |
| RMDX | American Refrigerator Transit Co. | 7/65-4/70; eliminated 4/74; 1/75-1/80; added 7/82; 1/94-7/2000 |
| RMGX | Railcar, Ltd. | added 10/89; 1/94-7/2000 |
| RMIX | Ready Mixed Concrete Co. | added 7/84; 1/94-7/2000 |
| RMJX | Rieck-McJunkin Dairy Co. | Apr-38 |
| RMMX | Railcar, Ltd. | added 4/94; 7/2000 |
| RMPX | Railcar, Ltd. | added 4/2000; 7/2000 |
| RMRR | Rocky Mountain Railcar and R.R., Inc. | added 10/87; eliminated 1/91; added 10/91; 1/94; eliminated 1/97; 7/2000 |
| RMSX | Pandrol Jackson, Inc. | Jan-94 |
| Harsco Track Technologies | Jul-00 | |
| RMX | Rowena Mathis | Apr-38 |
| RNDX | American Car and Foundry Division, ACF Industries Inc. -- temporary expiring 1Apr71 | Apr-70 |
| ACF Industries, Inc., Amcar Division -- temporary expiring 1Apr75 | Jan-75 | |
| ACF Industries, Inc., Amcar Division -- temporary expiring 1Jan81 | Jan-80 | |
| ACF Industries, Inc., Amcar Division | 1/94-7/2000 | |
| ACF Industries, Inc. | added 10/2000 | |
| RNGX | Rural Natural Gas Co. | 1/52-4/61 |
| RNSX | Rausch Naval Stores Co., Inc. | 1/52-10/66; eliminated 7/69 |
| RNWX | Rainey-Wood Coke Co. | Apr-38 |
| Alan Wood Steel Co. | 1/52; eliminated 4/54 | |
| ROCK | Chicago, Rock Island and Pacific Ry. Co. | added 7/75; 1/80; eliminated 7/80 |
| ROCX | Rock Island Improvement Co. | added 1/79; 1/80; eliminated 7/80 |
| Rocky Mountain Transportation Services | added 7/95; 7/2000 | |
| ROIX | Shintech Inc. | added 10/74; 1/75-7/2000; eliminated 4/2001 |
| ROKX | Alpha Crushed Stone, Inc. | eliminated 10/74 |
| ROLX | Robson Leather Co., Ltd. | added 7/60; 4/61-4/70; eliminated 7/70 |
| ROMX | Roy O. Martin Lumber Co., Inc. | added 10/68; 4/70; eliminated 1/71 |
| ROPX | Rail Operators, Inc. | added 7/93; 1/94; eliminated 4/97; 7/2000 |
| ROR | Rockton & Rion Ry. | 1/75-1/80 |
| RORX | Radio Oil Refineries, Ltd. | 4/38-1/52 |
| ROTX | Republic Oil Co. | Apr-38 |
| ROX | Richfield Oil Corporation | 4/38-7/65; eliminated 7/66 |
| Atlantic Richfield Co. | added 7/66; 10/66-4/70; eliminated 1/72 | |
| ROYX | TCL, Inc. | added 7/73; 1/75-1/80; eliminated 10/88 |
| ROYX | Chartrand's Tank Car Service, Inc. | eliminated 1/91 |
| RPAX | Rhone-Poulenc Basic Chemicals Co. | eliminated 10/92; 1/94 |
| RPBX | Rhone-Poulenc Basic Chemicals Co. | added 4/90; added 7/91; 1/94; eliminated 10/99 |
| Rhodia, Inc. | added 10/99; 7/2000 | |
| RPCX | Robeson Process Co. | 4/38-10/66; eliminated 10/69 |
| Ralston Purina Co. | added 1/74; 1/75-1/80; eliminated 7/89 | |
| RPHX | National Car Co. | Jan-52 |
| RPIX | Rhone-Poulenc Inc. | added 1/87; 1/94; eliminated 1/96; 7/2000 |
| RPOX | Refinery Products Co. | 7/65-10/66; eliminated 4/67 |
| Refinery Products Co., Division of QuVoe Chemical Industries, Inc. | added 4/67; 4/70; eliminated 7/70 | |
| RPRX | Rath Packing Co. (Mather Stock Car Co.) | 4/38-1/52 |
| Mather Stock Car Co. | eliminated 7/55 | |
| North American Car Corp. | added 7/55; eliminated 10/57; added 1/58; 4/61-1/80; eliminated 7/82 | |
| RPX | Roxana Petroleum Corp. (Shell Petroleum Corp.) | Apr-38 |
| RR | Raritan River R.R. Co. | 4/38-1/80; eliminated 7/80 |
| Consolidated Rail Corp. | added 10/80; 1/94; eliminated 7/99 | |
| RRBX | Rampart Range Corp. | added 4/94; eliminated 7/99; added 10/99; 7/2000 |
| RRCI | Redmont Ry. Co., Inc. | Jul-00 |
| RRCO | Rochelle R.R. Co. | Jul-00 |
| RRCX | Regent Refining (Canada) Ltd. | 10/57; eliminated 10/58 |
| Radar Railcar, Inc. | 1/94-7/2000 | |
| RREX | Rex Railways, Inc. | added 7/78; 1/80; eliminated 10/88 |
| Rex Railways, Inc. (transferred to Itel Rail Corp.) | added 10/88 | |
| Itel Rail Corp. | 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 | |
| RRIX | Rader Railcar II, Inc. | Jul-00 |
| RRRR | Rock & Rail, Inc. | Jul-00 |
| RRRX | Rex Leasing, Inc. | added 7/80; eliminated 1/87; added 7/87; eliminated 10/88 |
| Rex Leasing, Inc. (transferred to Itel Rail Corp.) | added 10/88 | |
| Itel Rail Corp. | eliminated 10/92 | |
| General Electric Railcar Services Corp. | added 10/92; eliminated 1/93 | |
| Rex Leasing, Inc. | added 1/93; 1/94-7/2000 | |
| RRVW | Red River Valley and Western R.R. | added 1/88; 1/94-7/2000 |
| RS | Roberval and Saguenay Ry. Co. | Apr-38 |
| Roberval-Saguenay Ry. | 1/52-4/70 | |
| Roberval and Saguenay Ry. Co. | 10/66 & 1/75-7/2000 | |
| RSB | Rochester Subway | 1/80-7/2000 |
| RSCX | Republic Steel Corp. | 4/38-4/70; eliminated 1/72 |
| RSEX | Riverside Chemical Co. | added 1/75; 1/75; eliminated 4/78 |
| RSGX | Merchants Despatch Transportation Corp. | 10/57-1/75; eliminated 7/79 |
| RSIX | The Reid Supply Co. | added 7/55; 10/57-4/61 |
| RSLX | RSL Corp. | added 10/78; 1/80; eliminated 10/84 |
| Shell Epoxy Resins | added 1/2001; eliminated 4/2001 | |
| Resolution Performance Products | added 4/2001 | |
| RSM | Railroad Switching Service of Missouri, Inc. | added 10/89; eliminated 7/91; 1/94-7/2000 |
| RSNR | Red Springs and Northern R.R. Co. | added 1/85; 1/94; eliminated 7/96; 7/2000 |
| RSOX | Shell Epoxy Resins | added 1/2001; eliminated 4/2001 |
| Resolution Performance Products | added 4/2001 | |
| RS&P | Roscoe, Snyder & Pacific Ry. | Apr-38 |
| RSP | Roscoe, Snyder & Pacific Ry. | 4/61 & 4/70-1/80; eliminated 1/89; eliminated 4/89 |
| Roscoe, Snyder and Pacific Ry. Co. | 1/94-7/2000 | |
| Roscoe, Snyder & Pacific Ry. | 7/65-10/66 | |
| RSPX | RSP Car Co. | added 7/60; 4/61-10/66; eliminated 4/70 |
| United States Railway Leasing Co. | added 4/70; 4/70; eliminated 7/70 | |
| United States Railway Equipment Co. | added 7/70; 1/75; eliminated 7/79 | |
| United States Leasing Co. | added 7/79 | |
| United States Railway Leasing Co. | 1/80; eliminated 10/80 | |
| Evans Railcar Leasing Co. | added 10/80; eliminated 4/88 | |
| Itel Rail Corp. | added 4/88; eliminated 10/92 | |
| General Electric Railcar Services Corp. | added 10/92; 1/94; eliminated 10/94 | |
| RSR | Rochester & Southern R.R., Inc. | added 10/86; eliminated 7/93; 1/94-7/2000 |
| RSRX | Revere Sugar Refinery | 10/57-1/75; eliminated 1/79 |
| RSS | Rockdale, Sandow & Southern R.R. Co. | 1/75-1/80; added 7/80; 1/94-7/2000 |
| RSTX | RSP Motor Transport Co. | added 4/69; 4/70; eliminated 1/72 |
| RSTX Inc. | added 1/72; 1/75-1/80; added 1/86; eliminated 10/88 | |
| RSUX | Riley Stoker Corp. | added 1/68; 4/70-1/94; eliminated 7/98; 7/2000 |
| RSVX | Railserv Management Corp. | added 4/80; eliminated 7/84 |
| Railserv Funding Corp. | eliminated 7/84; eliminated 7/86 | |
| RSYX | Refined Syrups & Sugars, Inc. | added 7/80; eliminated 7/81 |
| Refined Sugars, Inc. | added 7/81; eliminated 10/86; 1/94-7/2000 | |
| RSX | A.M. Richter Sons Co. | 4/38-10/57; eliminated 10/59 |
| RT | The River Terminal Ry. Co. | 4/38-7/2000 |
| RTA | Regional Transportation Authority | Jan-80 |
| RTCX | Republic Tank Car Co. | 1/52-4/61; eliminated 7/64 |
| Republic Car Line Inc. | added 7/64; 7/65-1/75; eliminated 7/77 | |
| Union Tank Car Co. | added 7/77; 1/80-7/2000 | |
| RTEX | Rosman Tanning Extract Co. | Apr-38 |
| Reese Tank Car Leasing Corp. | added 10/68; 4/70 | |
| Reese Enterprises, Inc. | 1/75; eliminated 1/79 | |
| Rail Trusts Equipment Inc. | Jul-00 | |
| RTIX | RTI--Railroad Services | Jul-00 |
| RTLX | Roby Tank Line (American Maize Products Co.) | Apr-38 |
| Relco Tank Line, Inc. | 7/65-10/66; eliminated 4/70 | |
| Relco Leasing Corp. | added 4/70; 4/70 | |
| Relco Tank Line | eliminated 1/72 | |
| Relco Tank Line, Inc. | added 1/72; 1/75 | |
| Relco Tank Line Division of Relco Nevada Corp. | 1/80; eliminated 10/86 | |
| Relco Tank Line, Inc. | added 10/86 | |
| Relco Leasing Corp. | Jan-94 | |
| Relco Tank Line, Inc. | Jul-00 | |
| RTM | The Railway Transfer Co. of the City of Minneapolis | 1/75-1/80; eliminated 4/84 |
| RTMX | Richmond Tank Car & Manufacturing Co. | added 4/68; eliminated 1/69; added 7/70; eliminated 10/70 |
| Marathon Leasing Co. | added 10/70 | |
| Richmond Leasing Co. | 1/75-1/80; eliminated 4/88 | |
| General Electric Railcar Services Corp. | added 4/88; 1/94; eliminated 1/2000 | |
| General Electric Rail Services Corp. | added 1/2000; 7/2000 | |
| RTPX | Wheelabrator Coal Services Co. | added 4/82; 1/94-7/2000; eliminated 4/2001 |
| Savage-Tolk Energy Services | added 4/2001 | |
| RTRX | E.I. du Pont de Nemours & Co., Inc. | added 7/63; 7/65; eliminated 1/66 |
| Rocky Mountain Transportation Services | added 7/95; 7/2000 | |
| RTSR | Rail Transportation Services, Inc. | added 7/96 |
| RTSX | Rail Transportation Services Inc. | Jul-00 |
| RTTX | Trailer Train Co. | 4/61-7/65 |
| Trailer Train Co. (FA flat cars equipped with tri-level automobile carrying superstructures furnished by member railroads. Cars are not equipped with hitches and bridge plates) | 10/66-10/68 | |
| Trailer Train Co. | Apr-70 | |
| Trailer Train Co. (flat cars, equipped with fixed tri-level auto racks furnished by participant railroads) | 1/75-1/80 | |
| Trailer Train Co. | eliminated 7/84 | |
| Trailer Train Co. | added 7/86; eliminated 1/92 | |
| TTX Co. | added 1/92 | |
| TTX Co. (89' and 178' TOFC Flat cars. 89' cars (6 digit car numbers other than 165000 series) are standard deck, 3-hitch flatcars with non-collapsable hitches at the ends of the car and a collapsable hitch at the centre of the car, capable of carrying 3 28' trailers with kingpin spacing of 36" or less, or any two trailers with 36" kingpin spacing, whose overall combined length does not exceed 90' -- i.e., 2-45', 1-42' & 1-48', 1-40' & 1-48', etc. -- between lift on/lift off facilities only. 178' cars (6 digit car numbers in 165000 series only) consist of two drawbar connected 89' units. Each unit has the same capabilities as the 89' RTTX cars described above) | 1/94-7/2000 | |
| RUDX | Ruddy Tank Car Co. | added 10/68; 4/70-7/2000 |
| RUSX | Resinera Uruapan, S. de R.L. | 1/52-4/70; eliminated 10/70 |
| Rail-U.S. Leasing, Inc. | added 4/73; 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 | |
| RUT | Vermont Ry., Inc. | 1/94-7/2000 |
| RUTX | Root Petroleum Co. | Apr-38 |
| RUX | The Ruberoid Co. | 4/38 & 10/57-4/61 |
| RV | Rahway Valley R.R. | 4/38-4/70 |
| Rahway Valley R.R. Co. (Rahway Valley Co., Lessee) | 1/75-1/80 | |
| Rahway Valley R.R. | eliminated 10/88 | |
| Rahway Valley R.R. Co. (transferred to New York, Susquehanna and Western Ry. Corp.) | added 10/88 | |
| Rahway Valley R.R. | eliminated 4/89 | |
| RVCX | Richter Vinegar Corp. | added 4/57; 10/57-1/80; eliminated 7/84 |
| RVLX | Reinhart Vinegars Ltd. | added 4/62; 7/65-1/75; eliminated 7/76 |
| RVPR | Riverport R.R., L.L.C. | Jul-00 |
| RVRR | Rio Valley R.R., Inc. | 1/94; added 4/94; eliminated 1/95; eliminated 4/95 |
| RVSC | Rio Valley Switching Co. | added 1/95; added 4/95; eliminated 7/96; eliminated 4/97; 7/2000; added 1/2001 |
| RWBX | Petroleum Fuels Co. | Jan-94 |
| RWCX | RWC, Inc. | 1/94-7/2000 |
| RWMX | Railway Management, Inc. | added 10/91; 1/94; eliminated 4/97 |
| RWSX | Scherer Electric Generating Facility | added 7/93; 1/94-7/2000 |
| RWTX | Railwest US, Inc. | added 7/98; 7/2000 |
| RX | Oklahoma Tank Car Co. | Apr-38 |