Here is a Marx O gauge 6 inch #51998 Chicago & Northwestern yellow sliding door boxcar with black details and white lettering.  It is a color combination that Marx apparently only used prior to WWII.  The car has 4 stamped metal wheels on metal axles, and riveted tab and slot style couplers, so this was likely in an electric train set.  The car has both of its original doors and looks great from MOST angles, BUT there is an area on one side towards the left end that has MAJOR litho loss and is basically just bare metal.  Pity!  This car would be an EXCELLENT shelf piece (that is what I used it for many a year until I got a better one in a collection I recently purchased).  I am sure someone out there will want this, either to fill a hold in their collection, or maybe just for those original doors (I am always amazed at how many of these 6-inch boxcars are missing doors).  Photos from all 6 sides, with a penny in the shots for size reference.  Priced to sell, with only actual USPS Ground Advantage or Priority shipping charged!