| 7901 | RREX | Rex Railways, Inc. | added 7/78; 1/80; eliminated 10/88 | | NRHS |
| 7902 | RREX | Rex Railways, Inc. (transferred to Itel Rail Corp.) | added 10/88 | | NRHS |
| 7903 | RREX | Itel Rail Corp. | eliminated 10/92 | | NRHS |
| 7904 | RREX | General Electric Railcar Services Corp. | added 10/92; 1/94; eliminated 1/2000 | | NRHS |
| 7905 | RREX | General Electric Rail Services Corp. | added 1/2000; 7/2000 | | NRHS |
| 7906 | RREX | *REX RAILWAYS INC. | | | PWRC |
| 7907 | RREX | +(NATX) GENERAL ELECTRIC RAIL SERVICES CORPORATION [ITEL RAIL CORP.] | | | PWRC |
| 7908 | RREX | Rex Railway | | | RSRV |
| 7909 | RREX | GENERAL ELECTRIC RAILCAR SERVICES C | | | SCAC4 |
| 7910 | RRF | UK Royal Positioning Flights (in military aircraft) | Callsign: Kitty, | GB | AVCODES |
| 7911 | RRF | Royal Air Force | | | ICAO1 |
| 7912 | RRF | Rotterdam Rail Feeding | Rotterdam Rail Feeding is a company providing shunting and hauling services to third parties. | NL | TRAFFIC |
| 7913 | RRF | Rotterdam Rail Feeding | | NL | VKM |
| 7914 | RRFA | REMORQUAGE R F A INC | | | SCAC4 |
| 7915 | RRFB | RED RIVER FARMS | | | SCAC4 |
| 7916 | RRFC | R & R FREIGHT SERVICE LLC | | | SCAC4 |
| 7917 | RRFE | RANGER REFRIGERATER EXPRESS INC | | | SCAC3 |
| 7918 | RRFE | RANGER REFRIGERATED EXPRESS INC | | | SCAC4 |
| 7919 | RRFI | R & R FERTILIZER INC | | | SCAC3 |
| 7920 | RRFI | R & R TRANSPORT | | | SCAC4 |
| 7921 | RRFM | RIDDLE & RIDDLE FARMS, INC | | | SCAC3 |
| 7922 | RRFN | R & R FREIGHT LINES LLC | | | SCAC4 |
| 7923 | RRFP | R & R FARM TRANSPORT | | | SCAC4 |
| 7924 | RRFQ | RICHMONDS REFRIGERATED TRUCKING CO | | | SCAC3 |
| 7925 | RRFQ | R & R FARMS | | | SCAC4 |
| 7926 | RRFS | ROAD RUNNERS FREIGHT SYSTEM INCORPO | | | SCAC3 |
| 7927 | RRFT | RIPPEL, RICHARD FARMING & TRUCKING | | | SCAC4 |
| 7928 | RRFW | R & R FREIGHTWAYS | | | SCAC3 |
| 7929 | RRFZ | (CSXT) RETIRED 04-06-93 ATP | | | PWRC |
| 7930 | RRGA | RO RO PARTNERS LTDC/O INTERORIENT N | | | SCAC4 |
| 7931 | RRGB | RIGEL REEDEREI GMBH & CO KG | | | SCAC4 |
| 7932 | RRGD | ROAD RANGER TRANSPORT LTD | | | SCAC4 |
| 7933 | RRGE | RIGEL REEDEREI GMBH & CO KG | | | SCAC4 |
| 7934 | RRGG | RIGEL REEDEREI GMBH & CO KG | | | SCAC4 |
| 7935 | RRGH | RIGEL REEDEREI GMBH & CO KG | | | SCAC4 |
| 7936 | RRGM | RIGEL BEREEDERUNGS GMBH & CO KG MT | | | SCAC4 |
| 7937 | RRGN | RIGEL REEDEREI GMBH & CO KG | | | SCAC4 |
| 7938 | RRGS | RIGEL REEDEREI GMBH & CO KG | | | SCAC4 |
| 7939 | RRGT | R & R TRUCKING | | | SCAC3 |
| 7940 | RRGV | RIGEL REEDEREI GMBH & CO KG | | | SCAC4 |
| 7941 | RRGW | RIGEL REEDEREI GMBH & CO KG MT WOLG | | | SCAC4 |
| 7942 | RRGX | Ranger Refining & Pipe Line Co. | 7/1923 | | NAKINA |
| 7943 | RRGX | RANGER REFINING & PIPE LINE CO. | | | PWRC |
| 7944 | RRGZ | (REAZ) RETIRED 04-06-93 ATP (ACI 2345) | | | PWRC |
| 7945 | RRHC | RENTRITE HAULAGE CORP | | | SCAC3 |
| 7946 | RRHH | R & R HEAVY HAUL | | | SCAC4 |
| 7947 | RRHI | ROBERTS, RANDY HAULING INC | | | SCAC4 |
| 7948 | RRHS | ROAD RUNNER HOTSHOT | | | SCAC3 |
| 7949 | RRI | Rhenus rail St.Ingbert GmbH | | DE | VKM |
| 7950 | RRIA | REGAL RIDGE | | | SCAC4 |
| 7951 | RRIC | ROBERTS, ROGER A INC | | | SCAC3 |
| 7952 | RRIF | RU RAN INC | | | SCAC4 |
| 7953 | RRII | RED RIVER INTERMODAL INC | | | SCAC3 |
| 7954 | RRII | RED RIVER INTERMODAL LLC | | | SCAC4 |
| 7955 | RRIL | ROLLS RIGHT INDUSTRIES LTD | | | SCAC3 |
| 7956 | RRIL | ROLLS RIGHT INDUSTRIES LTD | | | SCAC4 |
| 7957 | RRIN | R & R INVESTMENT CORP | | | SCAC3 |
| 7958 | RRIN | R-R INTERNATIONAL TRANSPORT LLC | | | SCAC4 |
| 7959 | RRIQ | REFRIGERANT RECYCLING INC | | | SCAC4 |
| 7960 | RRIU | Triton Containers | | | RSRV |
| 7961 | RRIU | TRITON CONTAINER INTERNATIONAL INC | | | SCAC4 |
| 7962 | RRIV | RED RIVER TRANSPORT OF COLORADO INC | | | SCAC3 |
| 7963 | RRIX | Rader Railcar II, Inc. | 7/2000-7/2005 (not listed) | | NAKINA |
| 7964 | RRIX | Rader Railcar II, Inc. | Jul-00 | | NRHS |
| 7965 | RRIX | RADER RAILCAR II INC. | | | PWRC |
| 7966 | RRIX | Rader Railcar | | | RSRV |
| 7967 | RRIX | RADER RAILCAR II INC | | | SCAC4 |
| 7968 | RRIY | R R I COMMODITY INC | | | SCAC4 |
| 7969 | RRJD | ROBERT, ROLAND J DISTRIBUTOR INC | | | SCAC4 |
| 7970 | RRJK | RRJ TRUCKING INC | | | SCAC4 |
| 7971 | RRJN | RIVERA ROJAS, JUAN | | | SCAC4 |
| 7972 | RRJO | RAMIRO, RIOS JASSO | | | SCAC4 |
| 7973 | RRJT | RUBEL, R J TRUCKING | | | SCAC3 |
| 7974 | RRK | Asia Continental Avialines | Callsign: Rufa, | KZ | AVCODES |
| 7975 | RRKA | RACER TRUCKING | | | SCAC4 |
| 7976 | RRKC | RUSHTRUCKING INC | | | SCAC3 |
| 7977 | RRKC | RANGE RIDER TRUCK CANOPIES | | | SCAC4 |
| 7978 | RRKD | ROUND ROBIN TRUCKING INC | | | SCAC4 |
| 7979 | RRKG | RHODES TRUCKING INC | | | SCAC3 |
| 7980 | RRKI | ROGERS & ROGERS TRUCKING CO | | | SCAC4 |
| 7981 | RRKL | RUSHON, R TRUCKING LP | | | SCAC4 |
| 7982 | RRKN | R & R TRUCKING | | | SCAC3 |
| 7983 | RRKN | R & R TRUCKING INC | | | SCAC4 |
| 7984 | RRKQ | RODERICK, F J & SON INC | | | SCAC3 |
| 7985 | RRKQ | RANGERACK INC | | | SCAC4 |
| 7986 | RRKT | RUSSELL, R K TRANSPORTATION LTD | | | SCAC4 |
| 7987 | RRKW | R & R TRUCKING CORPORATION | | | SCAC3 |
| 7988 | RRKW | R RELIABLE TRUCKING LLC | | | SCAC4 |
| 7989 | RRKY | R & R TRUCKING COMPANY | | | SCAC3 |
| 7990 | RRL | Rolls Royce Ltd. (Military Aviation) | Callsign: Merlin, | GB | AVCODES |
| 7991 | RRL | Rolls-Royce Limited | | | ICAO1 |
| 7992 | RRL | Rhenus Rail Logistics GmbH | Duisburg | D | privat-bahn.de |
| 7993 | RRL | Rail Release GmbH | | NL | VKM |
| 7994 | RRLA | RADIUS RAIL LOGISTICS LLC | | | SCAC4 |
| 7995 | RRLC | ROAD AND RAIL TRANSPORT INCORPORATE | | | SCAC4 |
| 7996 | RRLD | RITARA LIMITED | | | SCAC3 |
| 7997 | RRLE | ROADRUNNER LEDFOOT EXPRESS INC | | | SCAC3 |
| 7998 | RRLF | RITTER, R L FUEL INC | | | SCAC4 |
| 7999 | RRLG | ROADRUNNER LEASING INC | | | SCAC3 |
| 8000 | RRLH | ROLLING RIVER LIVE HAULING INC | | | SCAC4 |
