“Crossing Scale Boundaries” interesting topic! Items in one scale become useful and larger in smaller scales: round stirrers are pipes in O, HO, and N, wooden coffee stirrers for lumber loads, and ballast sizes, for example.
N scales buildings in the background create “forced perspective” in HO.
As an example: What scale is this item?
A small roof top water tank in O, a larger factory tank in HO, or a siding water tank in use or abandoned (depending on details/weathering) in N. It was built using a 35mm Kodak film canister as a first scratch build.
Plans, projects and techniques in magazines/audio-visual media for one scale can be used in others; thus any article has potential. This was an N scale kit plan that I scaled up and scratched in HO, for example. (Not finished)
Best, Steve Lynch
Trainsarefun.com – LIRR History 26th Year http://www.trainsarefun.com/lirr/lirrcontents.htm