| 8901 | RT | Rittgård Trading AB | | SE | VKM |
| 8902 | RTA | Regional Transportation Authority | 1/1980 | | NAKINA |
| 8903 | RTA | Regional Transportation Authority | Jan-80 | | NRHS |
| 8904 | RTA | REGIONAL TRANSPORTATION AUTHORITY (NOT AN OPERATING RAILROAD) | | | PWRC |
| 8905 | RTA | Regional Transportation Authority, Chicago | | USA | TRAFFIC |
| 8906 | RTAB | R & K TRUCKING | | | SCAC4 |
| 8907 | RTAC | ROWE | | | SCAC4 |
| 8908 | RTACA | Riverside Transit Agency | Real: RTA, City: Riverside | US-CA | TRAFFIC |
| 8909 | RTAD | RITE AID TRANSPORT INC | | | SCAC4 |
| 8910 | RTAE | RILO TRUCKING LLC | | | SCAC4 |
| 8911 | RTAF | Régie des transports de l'Aisne | | F | TRAFFIC |
| 8912 | RTAG | RISTVEBT TRUCKING & GRAIN SERVICE | | | SCAC3 |
| 8913 | RTAG | RISTVEDT TRUCKING AND GRAIN SERVICE | | | SCAC4 |
| 8914 | RTAH | RTA INTERNATIONAL INC | | | SCAC3 |
| 8915 | RTAJ | RARA TRANSPORT | | | SCAC4 |
| 8916 | RTAK | ROACH TRUCKING | | | SCAC4 |
| 8917 | RTAL | ROSEDALE TRANSPORT LTD | | | SCAC3 |
| 8918 | RTAL | ROSEDALE TRANSPORT LTD | | | SCAC4 |
| 8919 | RTAM | RICHARDS TRUCKING AND MESSENGER SER | | | SCAC3 |
| 8920 | RTAN | ROBBINS TRANSPORT INC | | | SCAC3 |
| 8921 | RTAO | ROSE TRANSPORTATION INC | | | SCAC3 |
| 8922 | RTAO | ROBERTS, T A OIL CO INC | | | SCAC4 |
| 8923 | RTAP | RAYS TRANSPORTATION INC | | | SCAC3 |
| 8924 | RTAP | RAM TRANSPORT INC | | | SCAC4 |
| 8925 | RTAR | ROTARY TECHNOLOGY INC | | | SCAC3 |
| 8926 | RTAS | RUGGED TRANSPORT | | | SCAC4 |
| 8927 | RTAT | REGIONAL TRANSIT AUTHORITY/ART INC, | | | SCAC3 |
| 8928 | RTAU | ROBOTANKS | | UA | BIC |
| 8929 | RTAW | ROSEWOODS TRANSPORTATION INC | | | SCAC4 |
| 8930 | RTAX | RENFE TALGO OF AMERICA, INC. | | | PWRC |
| 8931 | RTAX | RIO TINTO ALCAN | | | SCAC4 |
| 8932 | RTAY | RITEWAY TRANSPORTS LLC | | | SCAC4 |
| 8933 | RTB | Rurtalbahn GmbH | Düren | D | privat-bahn.de |
| 8934 | RTB | Rurtalbahn | former Dürener Kreisbahn | D | TRAFFIC |
| 8935 | RTB | Rurtalbahn | | DE | VKM |
| 8936 | RTBA | REMAL TRANSPORT LTD | | | SCAC4 |
| 8937 | RTBB | RENAISSANCE TRANSPORT LTD | | | SCAC4 |
| 8938 | RTBBG | Railway Tehnik Blgaria | | BG | VKM |
| 8939 | RTBC | RETUBECO INC | | | SCAC4 |
| 8940 | RTBC | RTB Cargo | | D | TRAFFIC |
| 8941 | RTBC | Rurtalbahn Cargo GmbH | | DE | VKM |
| 8942 | RTBD | RMA TRANSPORTATION SERVICES INC (IN | | | SCAC4 |
| 8943 | RTBE | ROTOBEC INC | | | SCAC4 |
| 8944 | RTBF | REESE TRANSPORT INC | | | SCAC4 |
| 8945 | RTBI | RUBENS TRUCK BROKERAGE INC | | | SCAC4 |
| 8946 | RTBO | ROCCOS | | | SCAC4 |
| 8947 | RTBO | RTB Rheintal Bus | | CH | TRAFFIC |
| 8948 | RTBORN | Rail Terminal Born | | NL | TRAFFIC |
| 8949 | RTBQ | REBA TRANSPORT LLC | | | SCAC4 |
| 8950 | RTBR | R & T BURNS INC | | | SCAC3 |
| 8951 | RTBT | ROOT, BOB TRUCKING INC | | | SCAC3 |
| 8952 | RTBU | RTSB GMBH | | D | BIC |
| 8953 | RTBV | RUPLINGER TRUCKING, LLC | | | SCAC4 |
| 8954 | RTC | Rail Traction Company | | I | TRAFFIC |
| 8955 | RTC | Rail Traction Company | | IT | VKM |
| 8956 | RTCA | RANDOLPH TRUCKING COMPANY INC | | | SCAC3 |
| 8957 | RTCA | ROOT CELLAR ANTIQUES | | | SCAC4 |
| 8958 | RTCC | RINEHOLD TRUCKING COMPANY INC | | | SCAC4 |
| 8959 | RTCD | RIGHT TRANSPORTATION CO | | | SCAC4 |
| 8960 | RTCF | RTCT TRANSPORT LTD | | | SCAC4 |
| 8961 | RTCH | RED & TAN CHARTER INC | | | SCAC3 |
| 8962 | RTCH | REGULATORY SOLUTIONS INC | | | SCAC4 |
| 8963 | RTCJ | RENES TRUCKING INC | | | SCAC4 |
| 8964 | RTCK | ROBIN TRUCK LINE INC | | | SCAC3 |
| 8965 | RTCL | RTC LTD | | | SCAC3 |
| 8966 | RTCM | RUSSELL TRANSPORT CORP | | | SCAC4 |
| 8967 | RTCN | RIVERVIEW TOURS CORPORATION | | | SCAC3 |
| 8968 | RTCN | R E TRUCKING | | | SCAC4 |
| 8969 | RTCO | RELIABLE TRANSFER CO | | | SCAC3 |
| 8970 | RTCP | R A C TRANSPORT COMPANY INC | | | SCAC3 |
| 8971 | RTCP | RATT INC | | | SCAC4 |
| 8972 | RTCQ | ROBERTS TRUCKING CO | | | SCAC3 |
| 8973 | RTCQ | Reseau de transport de la Capitale | Real: RTC, City: Quebec | CDN | TRAFFIC |
| 8974 | RTCR | RTC TRANSPORTATION INC (A DIV OF RO | | | SCAC3 |
| 8975 | RTCR | ROTEC INDUSTRIES INC | | | SCAC4 |
| 8976 | RTCSN | Regional Transportation Commission of Southern Nevada | City: Las Vegas | USA | TRAFFIC |
| 8977 | RTCT | RAINBOW TRUCKING CO AND CHEMICAL TR | | | SCAC3 |
| 8978 | RTCT | RTC LOGISTICS INC | | | SCAC4 |
| 8979 | RTCU | RAJ ORGOCHEM PVT LTD | | IND | BIC |
| 8980 | RTCU | OY RAILTRANS LTD | | | SCAC4 |
| 8981 | RTCX | Union Tank Car Co. | added 7/1977; 1/1980-7/2005 | | NAKINA |
| 8982 | RTCX | Republic Car Line Inc. | added 7/1964; 7/1965-1/1975; eliminated 7/1977 | | NAKINA |
| 8983 | RTCX | Republic Tank Car Co. | 1/1943-4/1961; eliminated 7/1964 | | NAKINA |
| 8984 | RTCX | Republic Tank Car Co. | 1/52-4/61; eliminated 7/64 | | NRHS |
| 8985 | RTCX | Republic Car Line Inc. | added 7/64; 7/65-1/75; eliminated 7/77 | | NRHS |
| 8986 | RTCX | Union Tank Car Co. | added 7/77; 1/80-7/2000 | | NRHS |
| 8987 | RTCX | (UTCX) UNION TANK CAR CO [REPUBLIC TANK CAR CO.] | | | PWRC |
| 8988 | RTCX | Republic Tank Car Co. (Union Tank Car) | | | RSRV |
| 8989 | RTCX | REPUBLIC CAR LINE INC | | | SCAC3 |
| 8990 | RTCX | UNION TANK CAR CO | | | SCAC4 |
| 8991 | RTCX | Republic Tank Car Co. | | USA | TRAFFIC |
| 8992 | RTCY | RICHARD TRANSPORT COMPANY INC | | | SCAC3 |
| 8993 | RTCY | R TWO (R2) LOGISTICS INC | | | SCAC4 |
| 8994 | RTCZ | Rocor Freight Services | | | RSRV |
| 8995 | RTCZ | ROCOR FREIGHT SERVICES | | | SCAC4 |
| 8996 | RTD | L-3 Communications Flight International Aviation, LLC | Callsign: Riptide, | USA | AVCODES |
| 8997 | RTD | Regional Transportation District | City: Denver | USA | TRAFFIC |
| 8998 | RTDA | ROOT, DALE S TRUCKING | | | SCAC3 |
| 8999 | RTDA | RUEST, DANIEL | | | SCAC4 |
| 9000 | RTDC | RAY'S TRANSPORT INC | | | SCAC4 |
