| Abbreviation | Definition |
|---|---|
| STRT | Stewartstown Railroad Company |
| STRU | Sea Star Line |
| STRX | St. Regis Paper |
| STRX | Trinity Industries Leasing Company |
| STRZ | Stroh/ Schlitz Brewery |
| STRZ | Stroh/Schlitz Brewery |
| STSX | A. E. Staley Manufacturing |
| STSX | A. E. Staley Manufacturing Company |
| STTU | Shirlstar Container Transport Limited |
| STTX | Trailer Train (TTX Corporation) |
| STTX | TTX Company |
| STTZ | Stevens Transport |
| STWX | Struthers Wells Corporation |
| STXU | Staxxon |
| SUAB | Southern Alabama Railroad |
| SUAB | Southern Alabama Railroad Company Inc |
| SUDU | Columbus Line |
| SUDU | Columbus Line Incorporated |
| SULX | Sultran |
| SULX | Sultran Limited |