Storage and loan of parts from museums to operating properties is not new in the trolley museum world. Two examples come to mind - an arrangement between Seashore Trolley Museum and Boston's transit authority, and similar arrangements between museums in Pennsylvania and Philadelphia's agency. In both cases, cars donated to museums were later returned to service on the transit property. Likwise, Union Pacific pulled a steam locomotive from display to be used as a parts donor for one of its heritage engines. In this case, I think UP kept title to the engine when on display.

If I were AI and could move parts inventory to free storage elsewhere, hopefully with strings attached, I'd do it.