| Abbreviation | Definition |
|---|---|
| SESU | Spinnaker Equipment Services |
| SESX | British Columbia Hydro |
| SESX | Sessions Co. (BC Hydro) |
| SFAL | SF and L Railway |
| SFCU | Steele Fabrication |
| SFIX | Helm Financial Corporation |
| SFIX | System Fuels |
| SFLC | Atchison, Topeka and Santa Fe Railway (BNSF Railway) |
| SFLC | Burlington Northern and Santa Fe Railway Company |
| SFLR | Shore Fast Line Incorporated |
| SFLR | Shore Fast Line Railroad |
| SFLRW | SFandL Railway Incorporated |
| SFPP | Spruce Fall Power and Paper |
| SFQ | Atchison, Topeka and Santa Fe Railway (BNSF Railway) |
| SFQ | Burlington Northern and Santa Fe Railway Company |
| SFR | Southern Freight Logistics LLC - Southern Freight Railroad |
| SFR | Southern Freight Railroad |
| SFRB | Atchison, Topeka and Santa Fe Railway (BNSF Railway) |
| SFRC | Atchison, Topeka and Santa Fe Railway (BNSF Railway) |
| SFRD | Atchison, Topeka and Santa Fe Railway (BNSF Railway) |