| 301 | RRPU | RESPOL RESINAS S.A. | | P | BIC |
| 302 | RRPX | RR Power Leasing LLC | added 10/2003; eliminated 1/2004; 7/2005 (not listed) | | NAKINA |
| 303 | RRPX | Ranger Refining & Pipe Line Co. | 8/1920-7/1923 | | NAKINA |
| 304 | RRPX | *RANGER REFINING & PIPE LINE CO. | | | PWRC |
| 305 | RRPX | +RR POWER LEASING LLC | | | PWRC |
| 306 | RRPX | Railroad Power Leasing | | | RSRV |
| 307 | RRPX | RR POWER LEASING LLC | | | SCAC4 |
| 308 | RRPX | Rail Road Power Leasing | | USA | TRAFFIC |
| 309 | RRPY | RIOUX, RUDY P | | | SCAC4 |
| 310 | RRQC | RED RIVER LOGISTICS LLC | | | SCAC4 |
| 311 | RRQS | R & R LOGISTIC SERVICE LLC | | | SCAC4 |
| 312 | RRR | RAF-HQSTC (Air Transport) | Callsign: Ascot/Kittyhawk, | GB | AVCODES |
| 313 | RRR | Royal Air Force | | | ICAO1 |
| 314 | RRRA | REGION RAIL REORG ACT (1973) TARIFF | | | SCAC3 |
| 315 | RRRC | RAIL ROAD RUNNER CONTAINER | | | SCAC4 |
| 316 | RRRE | RRR RECYCLING SERVICES HAWAII | | | SCAC4 |
| 317 | RRRF | R & R REFRIGERATED TRANSPORT | | | SCAC3 |
| 318 | RRRG | REMORQUAGE REAL GRAND MAISON | | | SCAC4 |
| 319 | RRRI | R & R TRUCKING | | | SCAC4 |
| 320 | RRRK | R & R TRANSPORTATION INC | | | SCAC4 |
| 321 | RRRO | RAINBOW MOVERS INC | | | SCAC4 |
| 322 | RRRP | RRR TRANSPORTATION INC | | | SCAC3 |
| 323 | RRRP | RRR TRANSPORTATION INC | | | SCAC4 |
| 324 | RRRR | Rock & Rail, Inc. | 7/2000-7/2005 | | NAKINA |
| 325 | RRRR | Rock & Rail, Inc. | Jul-00 | | NRHS |
| 326 | RRRR | ROCK & RAIL INCORPORATED | | | PWRC |
| 327 | RRRR | Rock & Rail Inc. | | | RSRV |
| 328 | RRRR | ROCK & RAIL INC | | | SCAC4 |
| 329 | RRRR | Rock & Rail, Inc. | | USA | TRAFFIC |
| 330 | RRRS | ROCK REMOVAL RESOURCES TRANSPORT LL | | | SCAC4 |
| 331 | RRRT | RAVAGNIE, RAYMOND R TRUCKING | | | SCAC3 |
| 332 | RRRT | R R R LOGISTICS LLC | | | SCAC4 |
| 333 | RRRU | REBLOCK CONTAINER AS. | | N | BIC |
| 334 | RRRU | R-CONTAINER IMPORT AS | | | SCAC4 |
| 335 | RRRX | Rex Leasing, Inc. | added 1/1993; 1/1994-7/2005 | | NAKINA |
| 336 | RRRX | General Electric Railcar Services Corp. | added 10/1992; eliminated 1/1993 | | NAKINA |
| 337 | RRRX | Itel Rail Corp. | eliminated 10/1992 | | NAKINA |
| 338 | RRRX | Rex Leasing, Inc. (transferred to Itel Rail Corp.) | added 10/1988 | | NAKINA |
| 339 | RRRX | Rex Leasing, Inc. | added 7/1980; eliminated 1/1987; added 7/1987; eliminated 10/1988 | | NAKINA |
| 340 | RRRX | Red River Refining Co., Inc. | 8/1920-7/1923 | | NAKINA |
| 341 | RRRX | Rex Leasing, Inc. | added 7/80; eliminated 1/87; added 7/87; eliminated 10/88 | | NRHS |
| 342 | RRRX | Rex Leasing, Inc. (transferred to Itel Rail Corp.) | added 10/88 | | NRHS |
| 343 | RRRX | Itel Rail Corp. | eliminated 10/92 | | NRHS |
| 344 | RRRX | General Electric Railcar Services Corp. | added 10/92; eliminated 1/93 | | NRHS |
| 345 | RRRX | Rex Leasing, Inc. | added 1/93; 1/94-7/2000 | | NRHS |
| 346 | RRRX | *RED RIVER REFINING CO., INC. | | | PWRC |
| 347 | RRRX | +REX LEASING, INC. [GENERAL ELECTRIC RAILCAR SERVICES CORP.; ITEL RAIL CORP.] | | | PWRC |
| 348 | RRRX | Rex Leasing | | | RSRV |
| 349 | RRRX | REX LEASING, INC. | | | SCAC4 |
| 350 | RRS | Boscombe Down DERA (Formation) | Callsign: Blackbox, Name changed from Boscombe Down DTEO (Formation) | GB | AVCODES |
| 351 | RRS | Boscombe Down DTEO (Formation) | Callsign: Blackbox, Name changed to Boscombe Down DERA (Formation). Name changed from RAE Bedford (RRS) | GB | AVCODES |
| 352 | RRS | RAE Bedford (RRS) | Callsign: Blackbox, Name changed to Boscombe Down DTEO (Formation) | GB | AVCODES |
| 353 | RRS | Boscombe Down DERA (Formation) | | | ICAO1 |
| 354 | RRS | RIMROCK STAGES | | | SCAC4 |
| 355 | RRSA | RED RIVER SPRAY-ON LTD | | | SCAC4 |
| 356 | RRSB | ROCKY RIDGE STABLES | | | SCAC4 |
| 357 | RRSI | RED RIVER SUPPLY INC | | | SCAC4 |
| 358 | RRSK | ROADRUNNER 66 TRUCKING INC | | | SCAC4 |
| 359 | RRSK | Regio Rail, s.r.o. | | SK | VKM |
| 360 | RRSL | RAJA ROADRAIL SERVICES LTD | | | SCAC4 |
| 361 | RRSO | RECYCLING RESOURCES | | | SCAC3 |
| 362 | RRSQ | REX, ROGER & SON TRUCKING INC | | | SCAC4 |
| 363 | RRSR | RRR EXPRESS | | | SCAC4 |
| 364 | RRSS | REED, R S & SONS INC | | | SCAC3 |
| 365 | RRST | RRS TRANSPORT INC | | | SCAC3 |
| 366 | RRST | RND RUSTICS | | | SCAC4 |
| 367 | RRSU | ARCTIC REEFER SERVICE & REPAIR B.V | | NL | BIC |
| 368 | RRSU | ARCTIC REEFER SERVICE & REPAIR B V | | | SCAC4 |
| 369 | RRSW | ROAD RUNNER SPECIALTY TOWING & TRAN | | | SCAC4 |
| 370 | RRT | Transportes Aereos Sierra Alta. S.A. de C.V. | Callsign: Sierra Alta, | MEX | AVCODES |
| 371 | RRT | Transportes Aereos Sierra | | | ICAO1 |
| 372 | RRTA | R & R TRANSPORTATION | | | SCAC3 |
| 373 | RRTA | ROAD RUNNER TRAILER MANUFACTURING L | | | SCAC4 |
| 374 | RRTB | R & R TRUCKING | | | SCAC3 |
| 375 | RRTC | RED RIVER TRUCKING COMPANY | | | SCAC3 |
| 376 | RRTD | R & R TRUCKING | | | SCAC3 |
| 377 | RRTE | R & R TRUCKING (HUMBERSTONE) LIMITE | | | SCAC3 |
| 378 | RRTE | R & R TRANSPORTATION | | | SCAC4 |
| 379 | RRTG | REEDER, ROBERT TRUCKING | | | SCAC3 |
| 380 | RRTH | R & R TRUCKING | | | SCAC3 |
| 381 | RRTH | REDRICK TECHNOLOGIES INC | | | SCAC4 |
| 382 | RRTI | R & R TRUCKING INC | | | SCAC3 |
| 383 | RRTI | R & R TRANSPORT INC | | | SCAC4 |
| 384 | RRTJ | RRT LOGISTICS INC | | | SCAC4 |
| 385 | RRTL | ROLLAND ROSE TRUCKING INC | | | SCAC4 |
| 386 | RRTM | R & R TRUCKING INC | | | SCAC3 |
| 387 | RRTN | RED RIVER TRANSPORTATION | | | SCAC3 |
| 388 | RRTO | RODRIGUEZ TRANSPORT | | | SCAC4 |
| 389 | RRTP | ROAD-RAIL TRANSPORTATION COMPANY | | | SCAC3 |
| 390 | RRTQ | ROADRUNNER TRUCKING, INC | | | SCAC3 |
| 391 | RRTQ | R & R TRUCKING | | | SCAC4 |
| 392 | RRTS | R & R TRUCKING SERVICE | | | SCAC3 |
| 393 | RRTT | R & R TRANSPORTATION COMPANY | | | SCAC3 |
| 394 | RRTV | R & R TRUCKING | | | SCAC3 |
| 395 | RRTX | *(TTX) UMLER TEST ROAD NO.14 | | | PWRC |
| 396 | RRTX | +RAILROAD TECHNOLOGY CORP. | | | PWRC |
| 397 | RRTX | RAILROAD TECHNOLOGY CORPORATION | | | SCAC4 |
| 398 | RRTY | R & R TRANSFER | | | SCAC3 |
| 399 | RRTY | ROBERTSONS TRANSPORT | | | SCAC4 |
| 400 | RRU | Cirrus, S.A. | Callsign: Helicirrus, | RCH | AVCODES |
