Tom Hokel (Pine Ridge RR)
I have that same boxcar. It's a Roundhouse …and one of their many G&D series. The "box" easily lifts off the frame. The number 5600 and the steps are a big clue.The "box" lifts off the frame.
Also, it may be the first commercial GD car ever offered. At least it was the first I ever saw … and purchased.
<PR> PINE RIDGE RR