| 1 | SRE | Simba Airlines Limited | Callsign: Simba Regional, | EAK | AVCODES |
| 2 | SRE | Fly Jetstream Aviation | Callsign: Streamjet, | ZA | AVCODES |
| 3 | SRE | Serami, C.A. | Callsign: Serami, | YV | AVCODES |
| 4 | SRE | Swiss Rail Europe | Basel | D | privat-bahn.de |
| 5 | SREA | SERGE & REAL COUTURE INC | | | SCAC4 |
| 6 | SREC | SOUTHWEST RAILWAY EQUIPMENT CORP. | | | PWRC |
| 7 | SREE | STAR REEFERS UK LTD | | | SCAC4 |
| 8 | SREG | SEADRUNAR RECYCLING | | | SCAC4 |
| 9 | SREI | SERVICE TRUCKING INC | | | SCAC4 |
| 10 | SREL | STERNS RENTAL CORP | | | SCAC4 |
| 11 | SREM | SIMS, REMEL | | | SCAC4 |
| 12 | SREN | SUN RIDGE ENTERPRISES LTD | | | SCAC4 |
| 13 | SRENN | Service des Transports en Commun de l'Agglomération Rennaise (STAR) | Real: STAR | F | TRAFFIC |
| 14 | SREO | STREAMLINE CARRIERS INC | | | SCAC4 |
| 15 | SREP | STELLA ROSA EXPRESS INC | | | SCAC4 |
| 16 | SREQ | STREETT TRUCKING LLC | | | SCAC4 |
| 17 | SRER | SURE CROP FEEDS | | | SCAC4 |
| 18 | SREU | SARENS NV | | B | BIC |
| 19 | SREW | SUNRISE EXPRESS, INC | | | SCAC1 |
| 20 | SREX | REA Express, Inc. | added 1/1971; eliminated 4/1974 | | NAKINA |
| 21 | SREX | StatesRail Equipment Co., LLC | 7/2000-7/2005 (not listed) | | NAKINA |
| 22 | SREX | REA Express, Inc. | eliminated 4/74 | | NRHS |
| 23 | SREX | StatesRail Equipment Co., LLC | Jul-00 | | NRHS |
| 24 | SREX | *REA EXPRESS, INC. | | | PWRC |
| 25 | SREX | +STATESRAIL EQUIPMENT COMPANY LLC | | | PWRC |
| 26 | SREX | StatesRail Equipment | | | RSRV |
| 27 | SREX | STATESRAIL EQUIPMENT COMPANY LLC | | | SCAC4 |
