Class 12
- ARD-12-class floating dry dock
- BBÖ 114
- BBÖ 214
- British Rail Class 12
- EAR 12 class
- India
- Indian locomotive class WAG-12
- JNR Class C12
- LSWR A12 class
- LSWR L12 class
- MGWR Class 12
- NSB Class 12
- New South Wales Z12 class locomotive
- O 12-class submarine
- PKP Class Ol12
- Prussian G 12
- Queensland A12 class locomotive
- SNCB Class 12
- SNCB Type 12
- Southern Pacific class AC-12
- Twelfth grade
- Type 12 (disambiguation)
- VR Class Dm12
- VR Class Dr12
- VR Class Dv12