Cast Iron Graf Zeppelin Toy - circa 1920's

Heavy 8.5" long vintage toy. Cast into side of envelope is "GRAF ZEPPLIN (sic)". Two cast wheels in front below control car and one in the rear forward of the lower vertical fin. Frankly, I don't understand how a child would use this since it is very top-heavy! Condition is quite good for its age; I would grade it fair-good.