All Engines

The umbrella grouping for vehicle propulsion engines across every transport mode this atlas tracks, sitting one level above the four mode-specific engine subcategories that already carry the detailed working scope: Automotive Engines, Aircraft Engines, Locomotive Engines and Marine Engines. Belongs here, at this coarse level: the category node itself and any future mode-specific engine subcategory this atlas adds; individual named engines are never minted directly under this node. Does not belong here: any specific named engine or engine family, which always belongs to whichever of the four existing subcategories matches its vehicle mode -- an engine entity minted directly under Engines rather than under, for example, Automotive Engines or Marine Engines, is filed one level too high.