Railroading
* British Rail Class 12, a British diesel locomotive class * DRG Class 12, a German steam locomotive class comprising the following eight-coupled, express locomotives operated by the Deutsche Reichsbahn: ** Class 12.0: BBÖ 214 ** Class 12.1: BBÖ 114 * EAR 12 class, steam locomotive * Indian locomotive class WAG-12, electric locomotive * JNR Class C12, steam locomotive * LSWR A12 class, steam locomotive * LSWR L12 class, steam locomotive * MGWR Class 12, steam locomotive * New South Wales Z12 class locomotive, steam locomotive * NSB Class 12, steam locomotive * PKP Class Ol12 * Queensland A12 class locomotive, steam locomotive * Prussian G 12 * SNCB Type 12, a Belgian steam locomotive * SNCB Class 12, a Belgian electric locomotive * Southern Pacific class AC-12, steam locomotive * VR Class Dm12, railcar * VR Class Dr12, diesel locomotive * VR Class Dv12, diesel locomotiveOther
* ARD-12-class floating dry dock * O 12-class submarine * Twelfth grade, referred to as "class 12" in IndiaSee also
* Type 12 (disambiguation) {{Disambig