Sounds like "hi rail" to me; what's the distinction, if any?
As originally practiced, hi-rail was 3-rail trains running in realistic scenery. It was all about the layout. A postwar scout pulling missile and helicopter launching cars on a layout with Gargraves track, ballast, hills and ground cover was hi-rail. As defined above, 3-rail scale is about making everything from trains to scenery to weathering to operation as realistic as possible.