| Abbreviation | Designation | |
|---|---|---|
| ABW | Außenbogenweiche (German) | railway installation |
| HSH | Hekurudha Shqiptarë, Hekurudha Shqiptarë SH.A. (Albanian) Albanian Railways | railway company |
| 21 / BY | Беларусь, Рэспубліка Беларусь (Belarusian) Belarus, Republic of Belarus | country code |
| 21 | BD Münster (1953–1974), Bundesbahndirektion Münster (German) | railway administration |