| 1 | RT | Airlines of South Australia | ICAO: LRT, Name changed from Lincoln Airlines Pty Ltd. | AUS | AVCODES |
| 2 | RT | Lincoln Airlines Pty Ltd. | ICAO: LRT, Name changed to Airlines of South Australia | AUS | AVCODES |
| 3 | RT | Transportes Aéreos de Timor | Callsign: TAT, | TL | AVCODES |
| 4 | RT | Air Tungaru | ICAO: TUN, Callsign: Tungaru, Desigantor RT recalled by IATA | KIR | AVCODES |
| 5 | RT | Air Turquoise SAS | ICAO: RTQ, Ceased operations on 02 August 2006. | F | AVCODES |
| 6 | RT | RAK Airways | ICAO: RKM, Callsign: Rakair, Founded in 2006. Suspended operations 01 January 2014. Desigantor RT recalled by IATA | UAE | AVCODES |
| 7 | RT | Rainbow Airlines (Private) Limited | ICAO: RAT, Callsign: Raindrop, Planned to commence operation on 25 January 2017. | ZW | AVCODES |
| 8 | RT | JSC UVT aero | ICAO: UVT, Callsign: Tat-Jet, Air Operators licence issued on 8th of July 2015. | RUS | AVCODES |
| 9 | RT | ISG Cleveland Works Ry. Co. d/b/a Cleveland Works Ry. Co. | added 10/2002; 7/2005 | | NAKINA |
| 10 | RT | The River Terminal Ry. Co. | 8/1920-7/2000; eliminated 10/2002 | | NAKINA |
| 11 | RT | The River Terminal Ry. Co. | 4/38-7/2000 | | NRHS |
| 12 | RT | *RIVER TERMINAL RAILWAY COMPANY | | | PWRC |
| 13 | RT | +ISG CLEVELAND WORKS RWY. CO. d/b/a CLEVELAND WORKS RWY. CO. | | | PWRC |
| 14 | RT | River Terminals Railway | | | RSRV |
| 15 | RT | | City: Reutlingen | D | TRAFFIC |
| 16 | RT | Rittgård Trading AB | | SE | VKM |
| 17 | RTA | Regional Transportation Authority | 1/1980 | | NAKINA |
| 18 | RTA | Regional Transportation Authority | Jan-80 | | NRHS |
| 19 | RTA | REGIONAL TRANSPORTATION AUTHORITY (NOT AN OPERATING RAILROAD) | | | PWRC |
| 20 | RTA | Regional Transportation Authority, Chicago | | USA | TRAFFIC |
| 21 | RTAB | R & K TRUCKING | | | SCAC4 |
| 22 | RTAC | ROWE | | | SCAC4 |
| 23 | RTACA | Riverside Transit Agency | Real: RTA, City: Riverside | US-CA | TRAFFIC |
| 24 | RTAD | RITE AID TRANSPORT INC | | | SCAC4 |
| 25 | RTAE | RILO TRUCKING LLC | | | SCAC4 |
| 26 | RTAF | Régie des transports de l'Aisne | | F | TRAFFIC |
| 27 | RTAG | RISTVEBT TRUCKING & GRAIN SERVICE | | | SCAC3 |
| 28 | RTAG | RISTVEDT TRUCKING AND GRAIN SERVICE | | | SCAC4 |
| 29 | RTAH | RTA INTERNATIONAL INC | | | SCAC3 |
| 30 | RTAJ | RARA TRANSPORT | | | SCAC4 |
| 31 | RTAK | ROACH TRUCKING | | | SCAC4 |
| 32 | RTAL | ROSEDALE TRANSPORT LTD | | | SCAC3 |
| 33 | RTAL | ROSEDALE TRANSPORT LTD | | | SCAC4 |
| 34 | RTAM | RICHARDS TRUCKING AND MESSENGER SER | | | SCAC3 |
| 35 | RTAN | ROBBINS TRANSPORT INC | | | SCAC3 |
| 36 | RTAO | ROSE TRANSPORTATION INC | | | SCAC3 |
| 37 | RTAO | ROBERTS, T A OIL CO INC | | | SCAC4 |
| 38 | RTAP | RAYS TRANSPORTATION INC | | | SCAC3 |
| 39 | RTAP | RAM TRANSPORT INC | | | SCAC4 |
| 40 | RTAR | ROTARY TECHNOLOGY INC | | | SCAC3 |
| 41 | RTAS | RUGGED TRANSPORT | | | SCAC4 |
| 42 | RTAT | REGIONAL TRANSIT AUTHORITY/ART INC, | | | SCAC3 |
| 43 | RTAU | ROBOTANKS | | UA | BIC |
| 44 | RTAW | ROSEWOODS TRANSPORTATION INC | | | SCAC4 |
| 45 | RTAX | RENFE TALGO OF AMERICA, INC. | | | PWRC |
| 46 | RTAX | RIO TINTO ALCAN | | | SCAC4 |
| 47 | RTAY | RITEWAY TRANSPORTS LLC | | | SCAC4 |
| 48 | RTB | Rurtalbahn GmbH | Düren | D | privat-bahn.de |
| 49 | RTB | Rurtalbahn | former Dürener Kreisbahn | D | TRAFFIC |
| 50 | RTB | Rurtalbahn | | DE | VKM |
| 51 | RTBA | REMAL TRANSPORT LTD | | | SCAC4 |
| 52 | RTBB | RENAISSANCE TRANSPORT LTD | | | SCAC4 |
| 53 | RTBBG | Railway Tehnik Blgaria | | BG | VKM |
| 54 | RTBC | RETUBECO INC | | | SCAC4 |
| 55 | RTBC | RTB Cargo | | D | TRAFFIC |
| 56 | RTBC | Rurtalbahn Cargo GmbH | | DE | VKM |
| 57 | RTBD | RMA TRANSPORTATION SERVICES INC (IN | | | SCAC4 |
| 58 | RTBE | ROTOBEC INC | | | SCAC4 |
| 59 | RTBF | REESE TRANSPORT INC | | | SCAC4 |
| 60 | RTBI | RUBENS TRUCK BROKERAGE INC | | | SCAC4 |
| 61 | RTBO | ROCCOS | | | SCAC4 |
| 62 | RTBORN | Rail Terminal Born | | NL | TRAFFIC |
| 63 | RTBQ | REBA TRANSPORT LLC | | | SCAC4 |
| 64 | RTBR | R & T BURNS INC | | | SCAC3 |
| 65 | RTBT | ROOT, BOB TRUCKING INC | | | SCAC3 |
| 66 | RTBU | RTSB GMBH | | D | BIC |
| 67 | RTBV | RUPLINGER TRUCKING, LLC | | | SCAC4 |
| 68 | RTC | Rail Traction Company | | I | TRAFFIC |
| 69 | RTC | Rail Traction Company | | IT | VKM |
| 70 | RTCA | RANDOLPH TRUCKING COMPANY INC | | | SCAC3 |
| 71 | RTCA | ROOT CELLAR ANTIQUES | | | SCAC4 |
| 72 | RTCC | RINEHOLD TRUCKING COMPANY INC | | | SCAC4 |
| 73 | RTCD | RIGHT TRANSPORTATION CO | | | SCAC4 |
| 74 | RTCF | RTCT TRANSPORT LTD | | | SCAC4 |
| 75 | RTCH | RED & TAN CHARTER INC | | | SCAC3 |
| 76 | RTCH | REGULATORY SOLUTIONS INC | | | SCAC4 |
| 77 | RTCJ | RENES TRUCKING INC | | | SCAC4 |
| 78 | RTCK | ROBIN TRUCK LINE INC | | | SCAC3 |
| 79 | RTCL | RTC LTD | | | SCAC3 |
| 80 | RTCM | RUSSELL TRANSPORT CORP | | | SCAC4 |
| 81 | RTCN | RIVERVIEW TOURS CORPORATION | | | SCAC3 |
| 82 | RTCN | R E TRUCKING | | | SCAC4 |
| 83 | RTCO | RELIABLE TRANSFER CO | | | SCAC3 |
| 84 | RTCP | R A C TRANSPORT COMPANY INC | | | SCAC3 |
| 85 | RTCP | RATT INC | | | SCAC4 |
| 86 | RTCQ | ROBERTS TRUCKING CO | | | SCAC3 |
| 87 | RTCQ | Reseau de transport de la Capitale | Real: RTC, City: Quebec | CDN | TRAFFIC |
| 88 | RTCR | RTC TRANSPORTATION INC (A DIV OF RO | | | SCAC3 |
| 89 | RTCR | ROTEC INDUSTRIES INC | | | SCAC4 |
| 90 | RTCSN | Regional Transportation Commission of Southern Nevada | City: Las Vegas | USA | TRAFFIC |
| 91 | RTCT | RAINBOW TRUCKING CO AND CHEMICAL TR | | | SCAC3 |
| 92 | RTCT | RTC LOGISTICS INC | | | SCAC4 |
| 93 | RTCU | RAJ ORGOCHEM PVT LTD | | IND | BIC |
| 94 | RTCU | OY RAILTRANS LTD | | | SCAC4 |
| 95 | RTCX | Union Tank Car Co. | added 7/1977; 1/1980-7/2005 | | NAKINA |
| 96 | RTCX | Republic Car Line Inc. | added 7/1964; 7/1965-1/1975; eliminated 7/1977 | | NAKINA |
| 97 | RTCX | Republic Tank Car Co. | 1/1943-4/1961; eliminated 7/1964 | | NAKINA |
| 98 | RTCX | Republic Tank Car Co. | 1/52-4/61; eliminated 7/64 | | NRHS |
| 99 | RTCX | Republic Car Line Inc. | added 7/64; 7/65-1/75; eliminated 7/77 | | NRHS |
| 100 | RTCX | Union Tank Car Co. | added 7/77; 1/80-7/2000 | | NRHS |
