Bob;

That particular car was in a small series of X31a converted from general service cars for coal tar chip service.  They had hatches added to load the chips through a hatch, not the doors.

There were a few of these wandering around in my day, and they looked entirely thrashed.

Some believed these cars were converted for flour, but I don’t buy it.  They were at the end of service life, and not good enough/tight/clean for flour service.  Besides, the one clear pic shows evidence of the tar drips down the side.

Tar chips were commonly used in the day for melting in either roof repair or road repair.  If a few chips missed the hatch, they gradually melted in the sun and dripped down.

Oh well.

Elden Gatwood