In 1960 my Dad took my Mom to a local auction and she bid on and won a 59 longbed, big back window fleetside like this one only it was a gorgeous turquoise and white. She bid $1200 and won. It had about 20k miles and was just like new. I drove it to school when she wasn't using it. Great truck.
The date only says summer of 1955 at the Proving Grounds. First - yeah, the bed! Second, they’re all over the place of FB what sort of device the trailer is. Some say it’s a load generator or a dynamometer. Anyone recognize it?