trucks with thick axles

[Nuttin But Flyer]

Looking at that photo close, it appears to be the die-cast chassis for an older style passenger coach or possibly a cattle car. Those holes resemble the place where brass chassis pins are normally inserted through it into the plastic body shell above to hold it on the chassis. I believe there were four pins, one in each corner, on the cattle car and six pins, adding two mid-way, on the passenger coaches. Without the body, it would look much like a plain flatcar.