| 9401 | RTRV | RAM TOUR & TRAVEL | | | SCAC3 |
| 9402 | RTRV | REEVES TRUCKING | | | SCAC4 |
| 9403 | RTRW | REDDEN TRUCKING | | | SCAC3 |
| 9404 | RTRX | Rocky Mountain Transportation Services | added 7/1995; 7/2000-7/2005 | | NAKINA |
| 9405 | RTRX | E.I. du Pont de Nemours & Co., Inc. | added 7/1963; 7/1965; eliminated 1/1966 | | NAKINA |
| 9406 | RTRX | E.I. du Pont de Nemours & Co., Inc. | added 7/63; 7/65; eliminated 1/66 | | NRHS |
| 9407 | RTRX | Rocky Mountain Transportation Services | added 7/95; 7/2000 | | NRHS |
| 9408 | RTRX | *E. I. DU PONT DE NEMOURS & CO., INC. | | | PWRC |
| 9409 | RTRX | *RAILTOWN 1897 RAILROAD | | | PWRC |
| 9410 | RTRX | +ROCKY MOUNTAIN TRANSPORTATION SERVICES | | | PWRC |
| 9411 | RTRX | Rocky Mountain Transportation Services | | | RSRV |
| 9412 | RTRX | ROCKY MOUNTAIN TRANSPORTATIN SERVIC | | | SCAC4 |
| 9413 | RTRY | RICHARDSON TRUCKING | | | SCAC4 |
| 9414 | RTRZ | ROAD TRAILER RENTALS LIMITED | | | PWRC |
| 9415 | RTRZ | Road Trailer Rentals Limited | | | RSRV |
| 9416 | RTRZ | ROAD TRAILER RENTALS, INC. | | | SCAC4 |
| 9417 | RTS | Relief Transport Services Ltd. | Callsign: Relief, | GB | AVCODES |
| 9418 | RTS | Relief Transport Services | | | ICAO1 |
| 9419 | RTS | Rail Transport Service Germany GmbH | München (Ableger von RTS Austria - Swietelsky) | D | privat-bahn.de |
| 9420 | RTS | RICHARDS TRANSPORTATION SERVICE INC | | | SCAC4 |
| 9421 | RTS | Rail Transport Service GmbH | | A | TRAFFIC |
| 9422 | RTS | RTS Rail Transport Service GmbH | | AT | VKM |
| 9423 | RTSA | RIVERSIDE TRUCK & STORAGE CO | | | SCAC3 |
| 9424 | RTSA | Rail Technical Support | Real: rts | AUS | TRAFFIC |
| 9425 | RTSB | RELIABLE TRANSPORTATION SOLUTIONS L | | | SCAC4 |
| 9426 | RTSC | RILEY TRUCKING SERVICE INC | | | SCAC3 |
| 9427 | RTSC | RTS | | | SCAC4 |
| 9428 | RTSC | RTS Rail Traction Services (Switzerland) AG | Real: RTS | CH | TRAFFIC |
| 9429 | RTSD | R T S TRUCKING LLC | | | SCAC4 |
| 9430 | RTSE | RTS ENTERPRISES | | | SCAC3 |
| 9431 | RTSF | RUTLAND TOOL SERVICE INC | | | SCAC3 |
| 9432 | RTSF | RUSSELLS TREE & SHRUB FARM LLC | | | SCAC4 |
| 9433 | RTSH | RT SYSTEMS INC | | | SCAC3 |
| 9434 | RTSI | ROBINHOOD TOWING SERVICE | | | SCAC3 |
| 9435 | RTSI | ROBINHOOD TOWING SERVICE | | | SCAC4 |
| 9436 | RTSJ | R T S TRANSPORTATION INC | | | SCAC3 |
| 9437 | RTSK | RUST & SONS TRUCKING INC | | | SCAC4 |
| 9438 | RTSL | RICHARDSON TRANSPORT LTD | | | SCAC3 |
| 9439 | RTSM | RTS TRANSPORTATION SYSTEMS INC | | | SCAC3 |
| 9440 | RTSN | RTS INVESTMENT CORPORATION | | | SCAC3 |
| 9441 | RTSN | REAVES TRANSPORTATION SERVICES LLC | | | SCAC4 |
| 9442 | RTSO | RAINS TRUCKING SERVICE INC | | | SCAC3 |
| 9443 | RTSQ | RAPID TRANSFER & STORAGE CO | | | SCAC3 |
| 9444 | RTSQ | RAPID TRANSFER & STORAGE CO | | | SCAC4 |
| 9445 | RTSR | Rail Transportation Services, Inc. | added 7/1996 | | NAKINA |
| 9446 | RTSR | Rail Transportation Services, Inc. | added 7/96 | | NRHS |
| 9447 | RTSR | RAIL TRANSPORTATION SERVICES, INC. | | | PWRC |
| 9448 | RTSR | RICHMOND TRAFFIC SERVICES INC | | | SCAC3 |
| 9449 | RTSRC | Regional Transit Service | in Riverside, California | USA | TRAFFIC |
| 9450 | RTSS | ROADCO TRANSPORTATION SERVICES, INC. | | | SCAC3 |
| 9451 | RTSS | ROADCO TRANSPORTATION SERVICES INC | | | SCAC4 |
| 9452 | RTST | ROOTS TRANSFER INC | | | SCAC3 |
| 9453 | RTSU | ROBERT KUKLA GMBH | | D | BIC |
| 9454 | RTSU | RENT TANK AG | | | SCAC3 |
| 9455 | RTSU | ROBERT KUKLA GMBH | | | SCAC4 |
| 9456 | RTSW | RAM TRANS SYSTEMS INC | | | SCAC3 |
| 9457 | RTSW | R T S | | | SCAC4 |
| 9458 | RTSX | Rail Transportation Services Inc. | 7/2000; eliminated 10/2002; 7/2005 (not listed) | | NAKINA |
| 9459 | RTSX | Rail Transportation Services Inc. | Jul-00 | | NRHS |
| 9460 | RTSX | RAIL TRANSPORTATION SERVICES, INC. | | | PWRC |
| 9461 | RTSX | Rail Transportation Services | | | RSRV |
| 9462 | RTSY | RAM TRANSPORT SYSTEMS INC | | | SCAC3 |
| 9463 | RTSY | RTS MOVING SERVICES | | | SCAC4 |
| 9464 | RTT | Titan Aero Airlines, Closed Joint-Stock Company | Callsign: Rustitan, | RUS | AVCODES |
| 9465 | RTT | RIVER TRAILS TRANSIT LINES INC | | | SCAC4 |
| 9466 | RTT | RAILTRANSPORT s.r.o. | | CZ | VKM |
| 9467 | RTTA | R T TRANSPORTATION INCORPORATED | | | SCAC3 |
| 9468 | RTTC | REFINERS TRANSPORT & TERMINAL CORPO | | | SCAC3 |
| 9469 | RTTD | R T TRANSPORT INC | | | SCAC3 |
| 9470 | RTTE | RT&T ENTERPRISES INC | | | SCAC4 |
| 9471 | RTTF | R & T TRANSPORT | | | SCAC3 |
| 9472 | RTTH | RITTER TRUCKING | | | SCAC3 |
| 9473 | RTTI | ROTTIER TRUCKING INC | | | SCAC3 |
| 9474 | RTTJ | RTTJ TRANSPORTATION INC | | | SCAC3 |
| 9475 | RTTK | R T TRUCKING INC | | | SCAC4 |
| 9476 | RTTL | REUTER, TODD TRUCKING LLC | | | SCAC4 |
| 9477 | RTTM | RYAN, TIM TRUCKING LLC | | | SCAC4 |
| 9478 | RTTN | R T TRANSPORTATION | | | SCAC4 |
| 9479 | RTTP | RITTER TRANSPORTATION | | | SCAC3 |
| 9480 | RTTP | Rīgas Tramvaju un Trolejbusu Pārvalde | City: Riga | LV | TRAFFIC |
| 9481 | RTTR | RTR TRANSPORTATION SERVICES | | | SCAC4 |
| 9482 | RTTS | R T T S INC | | | SCAC4 |
| 9483 | RTTT | RITTER TRUCKING | | | SCAC3 |
| 9484 | RTTU | RASA TECHNOLOGY TAIWAN LTD | | RC | BIC |
| 9485 | RTTU | RASA TECHNOLOGY TAIWAN LTD | | | SCAC4 |
| 9486 | RTTV | ROYS TOW & TRANSPORT SERV | | | SCAC3 |
| 9487 | RTTX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 9488 | RTTX | Trailer Train Co. | added 1/1961; 4/1961-1/1980; eliminated 7/1984; added 7/1986; eliminated 1/1992 | | NAKINA |
| 9489 | RTTX | Rapid Transit Tank Car Line | 7/1923 | | NAKINA |
| 9490 | RTTX | Trailer Train Co. (not defined) | added 1/1961; 4/1961 | | NAKINA |
| 9491 | RTTX | Trailer Train Co. (FCS flat cars equipped with tri-level automobile carrying superstructures furnished by member railroads. Cars are not equipped with hitches and bridge plates) | 4/1963 | | NAKINA |
| 9492 | RTTX | Trailer Train Co. (FA flat cars equipped with tri-level automobile carrying superstructures furnished by member railroads. Cars are not equipped with hitches and bridge plates) | 7/1965-10/1968 | | NAKINA |
| 9493 | RTTX | Trailer Train Co. (flat cars, equipped with fixed tri-level auto racks furnished by participant railroads) | 4/1970-1/1980 | | NAKINA |
| 9494 | RTTX | Trailer Train Co. | eliminated 7/1984 | | NAKINA |
| 9495 | RTTX | Trailer Train Co. (standard deck, 3-hitch flat cars with non-collapsible hitches at the ends of the car and a collapsible 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) | 7/1985 | | NAKINA |
| 9496 | RTTX | Trailer Train Co./TTX Co. (89' and 360' TOFC 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. 360 | added 7/1986; 10/1991-1/1992 | | NAKINA |
| 9497 | 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 | 1/1994-7/2000 | | NAKINA |
| 9498 | RTTX | Trailer Train Co. | 4/61-7/65 | | NRHS |
| 9499 | RTTX | Trailer Train Co. (FA flat cars equipped with tri-level automobile carrying superstructures furnished by member railroads. Cars are not equipped with hitches and bridge plates) | 10/66-10/68 | | NRHS |
| 9500 | RTTX | Trailer Train Co. | Apr-70 | | NRHS |
