The open top railroad car carrier was a 'target' every time the Teamster's Union 'went out' or some other worker's group went out on a strike. The news media, and the industry 'gossip' seemed to carry 'stories of 'incidents'. Debris being 'thrown or dropped' off overpasses onto loaded, open car carriers. Liquids being used to destroy paint of vehicles in transit. Those stories, and those tales were out there.
Seemed as if,it was in the late 1990's(?) that cars started to have structures built over their top decks. And over time, the current type, encclosed, auto transport car has evolved. Covered, shielded on their sides and with three decks; all to protect, and provide more room to transport the autos, and/or light trucks, throughout North America, and Mexico.