Thanks for adding more of the FRA's position, as I find this more interesting as we go along. I note they use the term 'revenue' switching and 'revenue' cars. At what point does an AAR interchange gondola (or many of them entrained like in the video that started this thread) become 'non-revenue' to revenue and/or back again?

Is it revenue when it arrives in a yard off through-freight, then becomes non-revenue when it is drafted into yeoman service for a work group, then becomes revenue again as it re-enters the switchyard to join the national fleet of interchange cars...now loaded with scrap steel from the work group to a far-off scrap broker?

Note that I continue to use the term AAR-interchange. There is a significant difference between white-lined or non-interchange company equipment reassigned to captive MOW service, and revenue, interchange cars or equipment. Example: much of UPRR's MOW equipment is painted vomit green and stenciled as MOW service, so did ATSF and Espee with theirs. The standards of inspection were far less, did not require AAR interchange and inspection standards, and were often maintained to a lesser degree of 'readiness', and most of the equipment's hallmark was that it was of advanced age. Yes, the equipment, when entrained still required FRA inspections.

So, why does the FRA inject the term 'revenue'...what is the basis for their isolation of this class of equipment, when non-revenue and often obsolete MOW equipment is also a consideration?