| 8301 | PRPX | Union Tank Car Co. | added 10/53; 10/57; eliminated 7/58 | | NRHS |
| 8302 | PRPX | *UNION TANK CAR CO. [TRANSIT CO. LTD.] | | | PWRC |
| 8303 | PRPX | +PACIFIC RAILROAD PRESERVATION ASSOCIATION | | | PWRC |
| 8304 | PRPX | Pacific Railroad Preservation Association | | | RSRV |
| 8305 | PRPX | PACIFIC RAILROAD PRESERVATION ASSOC | | | SCAC4 |
| 8306 | PRPY | PRICE LOGISTICS | | | SCAC4 |
| 8307 | PRPZ | PROCESS PLASTICS CO. | | | PWRC |
| 8308 | PRQ | PT. Pacific Royale Airways | IATA: RY, Callsign: Skyrider, Ceased operations in November 2012. Founded Nov 2011. Commenced operations 11 June 2012. ICAO designator changed from ROY. ICAO callsign changed to Paxroy. | RI | AVCODES |
| 8309 | PRQA | PARRS INC | | | SCAC4 |
| 8310 | PRQC | PRITCHETTS | | | SCAC3 |
| 8311 | PRQD | PERLMAN ROCQUE DIVISION | | | SCAC3 |
| 8312 | PRQD | PRIDE TRANSPORTATION CO INC | | | SCAC4 |
| 8313 | PRQE | PRIORITY EXPRESS INC | | | SCAC3 |
| 8314 | PRQE | PRIORITY EXPRESS INC | | | SCAC4 |
| 8315 | PRQF | PRAIRIE FUELS | | | SCAC4 |
| 8316 | PRQK | PRAIRIE TRUCKING INC | | | SCAC3 |
| 8317 | PRQL | PUERTO RICO LINE INC, SAN JUAN PR | | | SCAC3 |
| 8318 | PRQL | PR LOGISTICS LLC | | | SCAC4 |
| 8319 | PRQO | PROMISE TRANSPORT | | | SCAC4 |
| 8320 | PRQP | P & R EQUIPMENT | | | SCAC3 |
| 8321 | PRQP | PRAIRIE EQUIPMENT LTD | | | SCAC4 |
| 8322 | PRQR | PRUITT, RON TRUCKING | | | SCAC4 |
| 8323 | PRQS | PRECIOUS SHIPPING | | | SCAC3 |
| 8324 | PRQS | PRECIOUS SHIPPING | | | SCAC4 |
| 8325 | PRQT | PRIDE TRANSPORT INCORPORATED | | | SCAC3 |
| 8326 | PRQT | PRIDE TRANSPORT INCORPORATED | | | SCAC4 |
| 8327 | PRQV | PROFESSIONAL VALVE SERVICE LTD | | | SCAC4 |
| 8328 | PRR | Paramount Airlines Limited | Callsign: Paramount, | WAL | AVCODES |
| 8329 | PRR | Paramount Airlines | | | ICAO1 |
| 8330 | PRR | Norfolk Southern R.R. Co. (Norfolk Southern) | added 7/1999; 7/2000-7/2005 | | NAKINA |
| 8331 | PRR | Consolidated Rail Corp. | added 4/1976; 1/1980-1/1994; eliminated 7/1999 | | NAKINA |
| 8332 | PRR | Penn Central Transportation Co., Robert W. Blanchette, Richard C. Bond and John H. McArthur, Trustees | eliminated 4/1976 | | NAKINA |
| 8333 | PRR | Penn Central Transportation Co. | 4/1970-1/1975 | | NAKINA |
| 8334 | PRR | Pennsylvania R.R. | 4/1938-10/1966 | | NAKINA |
| 8335 | PRR | Pennsylvania R.R. | 4/38-10/66 | | NRHS |
| 8336 | PRR | Penn Central Transportation Co. | 4/70-1/75 | | NRHS |
| 8337 | PRR | Penn Central Transportation Co., Robert W. Blanchette, Richard C. Bond and John H. McArthur, Trustees | eliminated 4/76 | | NRHS |
| 8338 | PRR | Consolidated Rail Corp. | added 4/76; 1/80-1/94; eliminated 7/99 | | NRHS |
| 8339 | PRR | Norfolk Southern R.R. Co. (Norfolk Southern) | added 7/99; 7/2000 | | NRHS |
| 8340 | PRR | *P & R RAIL CAR SERVICE CORP. | | | PWRC |
| 8341 | PRR | +NORFOLK SOUTHERN RWY. [CONRAIL; PENN CENTRAL; PENNSYLVANIA RR] | | | PWRC |
| 8342 | PRR | Pennsylvania Railroad (Norfolk Southern) | | | RSRV |
| 8343 | PRR | PRESCOTT TRANSIT AUTHORITY | | | SCAC4 |
| 8344 | PRR | Pennsylvania Railroad | | USA | TRAFFIC |
| 8345 | PRRA | PREMIER TRANSPORT LTD | | | SCAC3 |
| 8346 | PRRC | PERROTT, SR CHARLES T | | | SCAC3 |
| 8347 | PRRD | PROMPT REFRIGERATED TRANSPORT INC | | | SCAC3 |
| 8348 | PRRE | PANKAR MARITIME S A | | | SCAC3 |
| 8349 | PRRE | PANKAR MARITIME S A | | | SCAC4 |
| 8350 | PRRF | PROMES, RAYNOLD F | | | SCAC3 |
| 8351 | PRRG | PERRY RIGGING AND STORAGE | | | SCAC3 |
| 8352 | PRRH | PARRISH TRUCKING CO INC | | | SCAC3 |
| 8353 | PRRH | PARRISH TRUCKING CO INC | | | SCAC4 |
| 8354 | PRRL | PARSONS, R L INC | | | SCAC3 |
| 8355 | PRRM | PRIORITY MAIL (DIV OF USPS) | | | SCAC3 |
| 8356 | PRRN | PRIOR TRUCKING CO | | | SCAC3 |
| 8357 | PRRN | PIRRONE, MIKE PRODUCE INC | | | SCAC4 |
| 8358 | PRRP | PARRCO ENTERPRISES | | | SCAC3 |
| 8359 | PRRP | PERRAS LUMBER INC | | | SCAC4 |
| 8360 | PRRQ | PARRY | | | SCAC3 |
| 8361 | PRRR | POIRIER, RICHARD | | | SCAC4 |
| 8362 | PRRS | PRIM RE-FER SERVICE INC | | | SCAC3 |
| 8363 | PRRT | PARSONS, ROBERT TRUCKING | | | SCAC3 |
| 8364 | PRRW | PREMIER TOURS | | | SCAC3 |
| 8365 | PRRX | Pennsylvania Lines LLC | 7/2000-7/2005 (not listed) | | NAKINA |
| 8366 | PRRX | Pennsylvania Lines LLC | Jul-00 | | NRHS |
| 8367 | PRRX | *PENNSYLVANIA RAILROAD HISTORICAL EQUIPMENT CORPORATION | | | PWRC |
| 8368 | PRRX | *POWELL RIVER RAILROAD COMPANY | | | PWRC |
| 8369 | PRRX | +PENNSYLVANIA LINES LLC | | | PWRC |
| 8370 | PRRX | Pennsylvania Railroad (Norfolk Southern) | | | RSRV |
| 8371 | PRRX | PENNSYLVANIA LINES LLC | | | SCAC4 |
| 8372 | PRS | Pars Air | Callsign: Pars Sky, | IR | AVCODES |
| 8373 | PRS | PEARL RIVER VALLEY RAILROAD CO. | | | PWRC |
| 8374 | PRSB | P R S CONSULTING GROUP INC | | | SCAC3 |
| 8375 | PRSC | PRECISION AIR CARGO | | | SCAC4 |
| 8376 | PRSD | PREMIER RECYCLING SARNIA LTD | | | SCAC4 |
| 8377 | PRSE | PRIORITY SERVICES INC | | | SCAC3 |
| 8378 | PRSE | PERISHABLE EXPRESS LLC | | | SCAC4 |
| 8379 | PRSF | PARSEC INC | | | SCAC3 |
| 8380 | PRSF | PRESTON, FRANK W TRUCKING | | | SCAC4 |
| 8381 | PRSG | PRSI TRADING COMPANY LP | | | SCAC4 |
| 8382 | PRSH | PROSHIPPING GROUP | | | SCAC4 |
| 8383 | PRSI | PRISCO (SINGAPORE) PTE LTD | | | SCAC4 |
| 8384 | PRSJ | PUERTO RICAN SHIPPING AGENCY INC | | | SCAC3 |
| 8385 | PRSJ | PROSHIPLINE | | | SCAC4 |
| 8386 | PRSK | PIERCESON TRUCKING INC | | | SCAC3 |
| 8387 | PRSK | PREUSSNER TRUCK LINES INC | | | SCAC4 |
| 8388 | PRSL | Consolidated Rail Corp. | 1/1980-1/1994 | | NAKINA |
| 8389 | PRSL | Pennsylvania-Reading Seashore Lines | 1/1975 | | NAKINA |
| 8390 | PRSL | Pennsylvania-Reading Seashore Lines | Jan-75 | | NRHS |
| 8391 | PRSL | Consolidated Rail Corp. | 1/80-1/94 | | NRHS |
| 8392 | PRSL | CONSOLIDATED RAIL CORP. [PENNSYLVANIA-READING SEASHORE LINES] | | | PWRC |
| 8393 | PRSL | Pennsylvania-Reading Seashore Lines (Norfolk Southern) | | | RSRV |
| 8394 | PRSL | PRESSLEY TRUCKING CO INC | | | SCAC3 |
| 8395 | PRSL | PRESLER CARRIERS LLC | | | SCAC4 |
| 8396 | PRSL | Pennsylvania-Reading Seashore Lines | | USA | TRAFFIC |
| 8397 | PRSM | PEERS MOVING COMPANY | | | SCAC3 |
| 8398 | PRSN | PRESNYA SHIPPING COMPANY LIMITED | | | SCAC3 |
| 8399 | PRSO | PORTLAND ROAD SERVICES | | | SCAC4 |
| 8400 | PRSP | PRECISION STRIP TRANSPORT INC | | | SCAC3 |
