On Wed, Aug 25, 2021 at 10:47 AM, Paul Koehler wrote:

Van type trailers to be used in Piggyback service must have doubled cam lock rear doors the chain or chicken wire rear enclosures were not legal for piggyback.

In the interest of completing this discussion of tarps on trailers, the chain gates, covered with a canvas curtain to keep out the weather, were typically used on "city trucks", those that made local deliveries on city streets, never on over-the-road trucks. Before the "TODCO" door was developed by the Truck Overhead Door Company, trucks were typically closed and sealed with two swinging doors, each 4' wide. These are a real pain, and dangerous., to open on a crowded city street, as the door has to swing into the traffic lane, so the sliding chain gate and curtain was much safer, if not as secure.

Dennis Storzek