Here is a Marx prewar O gauge 6 inch 2574 Barrel Car in black and in the 8 wheel version.  This one is decent, with signs of playwear and light surface rust on the exposed metal.  It has 8 stamped metal wheels on metal axles, and the "oneway" post and pinchers style couplers.  All 8 of the little separate journal boxes are also still present on the side frames. The post is the diecast metal version (they also had stamped steel posts).  The formed wire cradle pieces to hold the barrels are all here, but none of the 7 wooden barrels are still around (they do make reproduction barrels, though).  Photos from all 6 sides, with a yardstick in the shots for size reference.  Priced to sell, with only actual USPS Ground Advantage or Priority shipping charged!