| 1 | RT | ISG Cleveland Works Ry. Co. d/b/a Cleveland Works Ry. Co. | added 10/2002; 7/2005 | NAKINA | |
| 2 | RT | The River Terminal Ry. Co. | 8/1920-7/2000; eliminated 10/2002 | NAKINA | |
| 3 | RT | The River Terminal Ry. Co. | 4/38-7/2000 | NRHS | |
| 4 | RT | *RIVER TERMINAL RAILWAY COMPANY | PWRC | ||
| 5 | RT | +ISG CLEVELAND WORKS RWY. CO. d/b/a CLEVELAND WORKS RWY. CO. | PWRC | ||
| 6 | RT | River Terminals Railway | RSRV | ||
| 7 | RT | City: Reutlingen | D | TRAFFIC | |
| 8 | RT | Rittgård Trading AB | SE | VKM | |
| 9 | RTA | Regional Transportation Authority | 1/1980 | NAKINA | |
| 10 | RTA | Regional Transportation Authority | Jan-80 | NRHS | |
| 11 | RTA | REGIONAL TRANSPORTATION AUTHORITY (NOT AN OPERATING RAILROAD) | PWRC | ||
| 12 | RTA | Regional Transportation Authority, Chicago | USA | TRAFFIC | |
| 13 | RTAB | R & K TRUCKING | SCAC4 | ||
| 14 | RTAC | ROWE | SCAC4 | ||
| 15 | RTACA | Riverside Transit Agency | Real: RTA, City: Riverside | US- | TRAFFIC |
| 16 | RTAD | RITE AID TRANSPORT INC | SCAC4 | ||
| 17 | RTAE | RILO TRUCKING LLC | SCAC4 | ||
| 18 | RTAF | Régie des transports de l'Aisne | F | TRAFFIC | |
| 19 | RTAG | RISTVEBT TRUCKING & GRAIN SERVICE | SCAC3 | ||
| 20 | RTAG | RISTVEDT TRUCKING AND GRAIN SERVICE | SCAC4 | ||
| 21 | RTAH | RTA INTERNATIONAL INC | SCAC3 | ||
| 22 | RTAJ | RARA TRANSPORT | SCAC4 | ||
| 23 | RTAK | ROACH TRUCKING | SCAC4 | ||
| 24 | RTAL | ROSEDALE TRANSPORT LTD | SCAC3 | ||
| 25 | RTAL | ROSEDALE TRANSPORT LTD | SCAC4 | ||
| 26 | RTAM | RICHARDS TRUCKING AND MESSENGER SER | SCAC3 | ||
| 27 | RTAN | ROBBINS TRANSPORT INC | SCAC3 | ||
| 28 | RTAO | ROSE TRANSPORTATION INC | SCAC3 | ||
| 29 | RTAO | ROBERTS, T A OIL CO INC | SCAC4 | ||
| 30 | RTAP | RAYS TRANSPORTATION INC | SCAC3 | ||
| 31 | RTAP | RAM TRANSPORT INC | SCAC4 | ||
| 32 | RTAR | ROTARY TECHNOLOGY INC | SCAC3 | ||
| 33 | RTAS | RUGGED TRANSPORT | SCAC4 | ||
| 34 | RTAT | REGIONAL TRANSIT AUTHORITY/ART INC, | SCAC3 | ||
| 35 | RTAW | ROSEWOODS TRANSPORTATION INC | SCAC4 | ||
| 36 | RTAX | RENFE TALGO OF AMERICA, INC. | PWRC | ||
| 37 | RTAX | RIO TINTO ALCAN | SCAC4 | ||
| 38 | RTAY | RITEWAY TRANSPORTS LLC | SCAC4 | ||
| 39 | RTB | Rurtalbahn GmbH | Düren | D | privat-bahn.de |
| 40 | RTB | Rurtalbahn | former Dürener Kreisbahn | D | TRAFFIC |
| 41 | RTB | Rurtalbahn | DE | VKM | |
| 42 | RTBA | REMAL TRANSPORT LTD | SCAC4 | ||
| 43 | RTBB | RENAISSANCE TRANSPORT LTD | SCAC4 | ||
| 44 | RTBBG | Railway Tehnik Blgaria | BG | VKM | |
| 45 | RTBC | RETUBECO INC | SCAC4 | ||
| 46 | RTBC | RTB Cargo | D | TRAFFIC | |
| 47 | RTBC | Rurtalbahn Cargo GmbH | DE | VKM | |
| 48 | RTBD | RMA TRANSPORTATION SERVICES INC (IN | SCAC4 | ||
| 49 | RTBE | ROTOBEC INC | SCAC4 | ||
| 50 | RTBF | REESE TRANSPORT INC | SCAC4 | ||
| 51 | RTBI | RUBENS TRUCK BROKERAGE INC | SCAC4 | ||
| 52 | RTBO | ROCCOS | SCAC4 | ||
| 53 | RTBORN | Rail Terminal Born | NL | TRAFFIC | |
| 54 | RTBQ | REBA TRANSPORT LLC | SCAC4 | ||
| 55 | RTBR | R & T BURNS INC | SCAC3 | ||
| 56 | RTBT | ROOT, BOB TRUCKING INC | SCAC3 | ||
| 57 | RTBV | RUPLINGER TRUCKING, LLC | SCAC4 | ||
| 58 | RTC | Rail Traction Company | I | TRAFFIC | |
| 59 | RTC | Rail Traction Company | IT | VKM | |
| 60 | RTCA | RANDOLPH TRUCKING COMPANY INC | SCAC3 | ||
| 61 | RTCA | ROOT CELLAR ANTIQUES | SCAC4 | ||
| 62 | RTCC | RINEHOLD TRUCKING COMPANY INC | SCAC4 | ||
| 63 | RTCD | RIGHT TRANSPORTATION CO | SCAC4 | ||
| 64 | RTCF | RTCT TRANSPORT LTD | SCAC4 | ||
| 65 | RTCH | RED & TAN CHARTER INC | SCAC3 | ||
| 66 | RTCH | REGULATORY SOLUTIONS INC | SCAC4 | ||
| 67 | RTCJ | RENES TRUCKING INC | SCAC4 | ||
| 68 | RTCK | ROBIN TRUCK LINE INC | SCAC3 | ||
| 69 | RTCL | RTC LTD | SCAC3 | ||
| 70 | RTCM | RUSSELL TRANSPORT CORP | SCAC4 | ||
| 71 | RTCN | RIVERVIEW TOURS CORPORATION | SCAC3 | ||
| 72 | RTCN | R E TRUCKING | SCAC4 | ||
| 73 | RTCO | RELIABLE TRANSFER CO | SCAC3 | ||
| 74 | RTCP | R A C TRANSPORT COMPANY INC | SCAC3 | ||
| 75 | RTCP | RATT INC | SCAC4 | ||
| 76 | RTCQ | ROBERTS TRUCKING CO | SCAC3 | ||
| 77 | RTCQ | Reseau de transport de la Capitale | Real: RTC, City: Quebec | CDN | TRAFFIC |
| 78 | RTCR | RTC TRANSPORTATION INC (A DIV OF RO | SCAC3 | ||
| 79 | RTCR | ROTEC INDUSTRIES INC | SCAC4 | ||
| 80 | RTCSN | Regional Transportation Commission of Southern Nevada | City: Las Vegas | USA | TRAFFIC |
| 81 | RTCT | RAINBOW TRUCKING CO AND CHEMICAL TR | SCAC3 | ||
| 82 | RTCT | RTC LOGISTICS INC | SCAC4 | ||
| 83 | RTCU | OY RAILTRANS LTD | SCAC4 | ||
| 84 | RTCX | Union Tank Car Co. | added 7/1977; 1/1980-7/2005 | NAKINA | |
| 85 | RTCX | Republic Car Line Inc. | added 7/1964; 7/1965-1/1975; eliminated 7/1977 | NAKINA | |
| 86 | RTCX | Republic Tank Car Co. | 1/1943-4/1961; eliminated 7/1964 | NAKINA | |
| 87 | RTCX | Republic Tank Car Co. | 1/52-4/61; eliminated 7/64 | NRHS | |
| 88 | RTCX | Republic Car Line Inc. | added 7/64; 7/65-1/75; eliminated 7/77 | NRHS | |
| 89 | RTCX | Union Tank Car Co. | added 7/77; 1/80-7/2000 | NRHS | |
| 90 | RTCX | (UTCX) UNION TANK CAR CO [REPUBLIC TANK CAR CO.] | PWRC | ||
| 91 | RTCX | Republic Tank Car Co. (Union Tank Car) | RSRV | ||
| 92 | RTCX | REPUBLIC CAR LINE INC | SCAC3 | ||
| 93 | RTCX | UNION TANK CAR CO | SCAC4 | ||
| 94 | RTCX | Republic Tank Car Co. | USA | TRAFFIC | |
| 95 | RTCY | RICHARD TRANSPORT COMPANY INC | SCAC3 | ||
| 96 | RTCY | R TWO (R2) LOGISTICS INC | SCAC4 | ||
| 97 | RTCZ | Rocor Freight Services | RSRV | ||
| 98 | RTCZ | ROCOR FREIGHT SERVICES | SCAC4 | ||
| 99 | RTD | Regional Transportation District | City: Denver | USA | TRAFFIC |
| 100 | RTDA | ROOT, DALE S TRUCKING | SCAC3 |