THE MERRYMOBILE

Merrymobile ice cream vending truck.

Press release caption reads: "Merrymobile - colorful ice cream vending vehicle - built by Merrymobile Co., Memphis, Tennessee. Unit is powered by International UC-60 LP-Gas engine. Twenty-one International-powered Merrymobiles have been built, with 100 more on tap 1959
Boy this would put the "Good Humor" on guard!
(Wisconsin Historical Society Web Site)