| Abbreviation | Designation | |
|---|---|---|
| Os | Arriva Express (Czech) | train category |
| Os | Osobní vlak (Czech) | train category |
| Os | Osobowy (Polish) | train category |
| OS | Osnabrück Hbf, Stadt Osnabrück (German) | fare point / vehicle registration plate |
| Os | Orrskog (Swedish) | station code |
| Ös | Östersund C, Östersunds central (Swedish) | station code |
| OS | Compagnie de l'Ouest-Suisse (France) | railway company |