Ok Folks more information on the trailers.
I just talked to Howard Shaft the Trailways driver who was the driver who told the story.
The cargo trailers were about 8' wide by 10' long single axle with electric brakes.
The hitch on the PD4104's were a military style Pindle hitch.
The trailers were ballanced when loaded with freight so very little tounge weight on the bus and the hitch.
Wichita,Kansas was Continental Central Lines main body shop where the PD4104 reworked to haul the trailers.