| 9501 | RTTX | Trailer Train Co. (flat cars, equipped with fixed tri-level auto racks furnished by participant railroads) | 1/75-1/80 | | NRHS |
| 9502 | RTTX | Trailer Train Co. | eliminated 7/84 | | NRHS |
| 9503 | RTTX | Trailer Train Co. | added 7/86; eliminated 1/92 | | NRHS |
| 9504 | RTTX | TTX Co. | added 1/92 | | NRHS |
| 9505 | RTTX | 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 dig | 1/94-7/2000 | | NRHS |
| 9506 | RTTX | *RAPID TRANSIT TANK CAR LINE | | | PWRC |
| 9507 | RTTX | +TTX COMPANY | | | PWRC |
| 9508 | RTTX | TTX Corporation | | | RSRV |
| 9509 | RTTX | TTX COMPANY | | | SCAC4 |
| 9510 | RTTY | ROCKY TOP TRUCKING | | | SCAC4 |
| 9511 | RTTZ | UP [(REAZ) RETIRED 04-06-93 ATP (ACI 2384)] | | | PWRC |
| 9512 | RTTZ | Union Pacific Railroad | | | RSRV |
| 9513 | RTU | Aerotucan, S.A. de C.V. | Callsign: Aerotucan, | MEX | AVCODES |
| 9514 | RTU | Aerotucan | | | ICAO1 |
| 9515 | RTUC | R & R TRUCKING | | | SCAC3 |
| 9516 | RTUC | R & T TRUCK INC | | | SCAC4 |
| 9517 | RTUD | RENTALS UNLIMITED INC | | | SCAC3 |
| 9518 | RTUE | RODAN TRANSPORT USA LTD | | | SCAC4 |
| 9519 | RTUG | RATH TRUCKING, INC | | | SCAC3 |
| 9520 | RTUG | RATH TRUCKING INC | | | SCAC4 |
| 9521 | RTUI | RUSSELL TRUCKING INC | | | SCAC3 |
| 9522 | RTUL | Rail Technologie und Logistics GmbH | Magdeburg | D | privat-bahn.de |
| 9523 | RTUL | ROLLEN TRUCK LINES INC | | | SCAC3 |
| 9524 | RTUL | Rail Rechnology & Logistics GmbH | | DE | VKM |
| 9525 | RTUN | RTS TRUCKING CO | | | SCAC3 |
| 9526 | RTUQ | RTL TRUCKING LTD | | | SCAC4 |
| 9527 | RTUS | RATLIFFS TRUCKING SERVICE INC | | | SCAC3 |
| 9528 | RTV | Nortavia | Callsign: Tic-Tac, | P | AVCODES |
| 9529 | RTV | Nortavia | | | ICAO1 |
| 9530 | RTVA | R & T TRUCKING INC | | | SCAC3 |
| 9531 | RTVC | ROAD TRIP TOURS | | | SCAC3 |
| 9532 | RTVE | R T EXPRESS | | | SCAC4 |
| 9533 | RTVI | R T SERVICES INC | | | SCAC3 |
| 9534 | RTVL | ROBYNS TRUCKING SEVICES LTD | | | SCAC3 |
| 9535 | RTVR | RETRIEVER TRANSPORTATION INC | | | SCAC4 |
| 9536 | RTVS | RELIABLE TRANSPORT SERVICES | | | SCAC4 |
| 9537 | RTVU | DAILY RENTAL SERVICES BV | | NL | BIC |
| 9538 | RTW | Rail To Water | | USA | TRAFFIC |
| 9539 | RTWA | RITEWAY TRANSFER | | | SCAC3 |
| 9540 | RTWD | ROUND THE WORLD (USA) CORP. | | | SCAC3 |
| 9541 | RTWD | R TWO (R2) LOGISTICS INC (LTL DIVIS | | | SCAC4 |
| 9542 | RTWE | RTW ENTERPRISES | | | SCAC3 |
| 9543 | RTWE | RTW ENTERPRISES INC | | | SCAC4 |
| 9544 | RTWF | READS TOWING | | | SCAC3 |
| 9545 | RTWH | REDWAY TRUCK & WAREHOUSE COMPANY | | | SCAC3 |
| 9546 | RTWH | RAIL TRANSFER AND WAREHOUSING INC | | | SCAC4 |
| 9547 | RTWK | ROSS TOWING AND TRANSPORTATION SERV | | | SCAC4 |
| 9548 | RTWP | RITE-WAY TRANSPORTATION INC | | | SCAC3 |
| 9549 | RTWQ | RITEWAY MOTOR FRT CO | | | SCAC3 |
| 9550 | RTWQ | RITEWAY MOTOR FRT CO | | | SCAC4 |
| 9551 | RTWR | ROAD-RUNNER TOWING & RECOVERY | | | SCAC3 |
| 9552 | RTWR | RONS TOWING AND RECOVERY INC | | | SCAC4 |
| 9553 | RTWT | RITE WAY TRANSPORTATION INC | | | SCAC3 |
| 9554 | RTWT | RITE WAY TRANSPORTATION INC | | | SCAC4 |
| 9555 | RTWY | RITE-WAY TRANSPORT COMPANY INC | | | SCAC3 |
| 9556 | RTWY | RITE-WAY TRANSPORT COMPANY INC | | | SCAC4 |
| 9557 | RTX | Railtraxx BVBA | | BE | VKM |
| 9558 | RTXA | RELIABLE TRANSPORTATION | | | SCAC4 |
| 9559 | RTXC | R TRANSPORTATION LLC | | | SCAC4 |
| 9560 | RTXD | RENEW TRANSPORTATION LLC | | | SCAC4 |
| 9561 | RTXE | RELIANT TRANSPORT INC | | | SCAC4 |
| 9562 | RTXG | RTX LOGISTICS | | | SCAC4 |
| 9563 | RTXH | ROLYNNS TRANSPORTATION INC | | | SCAC4 |
| 9564 | RTXI | RAYTRUX INC | | | SCAC3 |
| 9565 | RTXI | ROMERO TRUCK EXPORTATION | | | SCAC4 |
| 9566 | RTXJ | REDWOOD TRANSPORT INC | | | SCAC4 |
| 9567 | RTXK | ROUNDTREE TRANSPORT LLC | | | SCAC4 |
| 9568 | RTXL | READY TAXI AND LIMOUSINE INC | | | SCAC3 |
| 9569 | RTXM | ROE TRANSPORT INC | | | SCAC4 |
| 9570 | RTXO | ROCKSTAR TRANSPORTATION INC | | | SCAC4 |
| 9571 | RTXP | RAPID TRANSFER XPRESS | | | SCAC4 |
| 9572 | RTXS | ROM TRANS EXPRESS INC | | | SCAC4 |
| 9573 | RTXV | ROORDA TRANSPORT CO | | | SCAC4 |
| 9574 | RTXW | RUETHER TRANSPORTATION INC | | | SCAC4 |
| 9575 | RTXY | RITTER TRANSPORTATION SYSTEMS INC | | | SCAC4 |
| 9576 | RTY | Aims Community College | Callsign: Aims College, | USA | AVCODES |
| 9577 | RTYE | ROAD TRAIN EXPRESS INC | | | SCAC4 |
| 9578 | RTYI | ROBERTS, TOMMY TRUCKING INC | | | SCAC4 |
| 9579 | RTYS | RASMUSON, TYSON | | | SCAC4 |
| 9580 | RTYT | REYNA TRUCKING INC | | | SCAC4 |
| 9581 | RTZ | Regional Air Services | Callsign: Aerotuzla, | RO | AVCODES |
| 9582 | RTZA | RETZLAFF, BRIAN TRUCKING | | | SCAC4 |
| 9583 | RTZB | ROTZ, BRUCE | | | SCAC4 |
| 9584 | RTZC | R T Z TRUCKING COMPANY LLC | | | SCAC4 |
| 9585 | RTZF | RETZLAFF, ARTHUR | | | SCAC3 |
| 9586 | RTZF | RATZLAFF TRANSPORT | | | SCAC4 |
| 9587 | RTZG | RED TAZZ EXPRESS BROKERAGE AND LOGI | | | SCAC4 |
| 9588 | RTZK | RADDATZ, KEN TRUCKING | | | SCAC3 |
| 9589 | RTZL | REITZ OIL COMPANY | | | SCAC4 |
| 9590 | RTZN | RH TWO ZERO (RH2O) NORTH AMERICA | | | SCAC4 |
| 9591 | RTZO | RITTZO TRUCKING | | | SCAC3 |
| 9592 | RTZP | RITZ-TRANS CORPORATION OF PENNSYLVA | | | SCAC4 |
| 9593 | RTZS | RENTZ FARM SUPPLY | | | SCAC3 |
| 9594 | RU | TCI Skyking Ltd. | ICAO: SKI, Callsign: Skyking, Founded in 1994. Ceased operations on 22 October 2008 on as merged into Air Turks and Caicos. Desigantor RU* reinstated by IATA | USA | AVCODES |
| 9595 | RU | SATA | | CH | AVCODES |
| 9596 | RU | Rousseau Aviation | | F | AVCODES |
| 9597 | RU | Compagnie de Transport Aerien (CTA) | ICAO: CTA, Callsign: CTA, Desigantor RU recalled by IATA | CH | AVCODES |
| 9598 | RU | AirBridge Cargo Airlines Limited | ICAO: ABW, Callsign: AirBridge Cargo, IATA Prefix: 580, IATA designator changed from BO. Founded in 2004. | RUS | AVCODES |
| 9599 | RU | Ryazan'- Urals Railway | | RU | TRAFFIC |
| 9600 | RUA | Rwanda Airlines | IATA: 9R, Designator 9R recalled by IATA | RWA | AVCODES |
