Here is a Marx O gauge X-246 Chemical Rocket Fuel single dome tank car, in white (some call it creme) plastic with red lettering.  It has 4 stamped metal wheels on metal axles, and plastic knuckle couplers on both ends (one coupler missing a small piece on the end but still functions).  Signs of playwear but intact and presentable.   Photos show the car from all 6 sides, with a penny in the shots for size reference.  Priced to sell, with only actual USPS Ground Advantage or Priority Mail shipping cost charged to the winner!