This Marx Emergency Rescue Tank was one of a series of similar vehicles produced in the 1970s. They all seem to have been very narrow, with a hollow 'cut-away' body so figures could be placed inside. There were at least four models: the Tank, a Truck, Submarine, and Helicopter. All came with a selection of rescue equipment. Here is a site with more information, the models are well down the page:http://www.angelfire.com/biz/toysoldierhq/Marxww.html The tank looks to be loosely based on the US Army M52 self-propelled gun of the 1950s, which was armed with a 105 mm howitzer. However, the body is shorter, with one less road wheel and one less return roller per side, and a longer gun barrel. There were actually several similar vehicles, of various sizes, mounting guns of various calibres.I have never even seen any of these toys before, but the open sides look like a good idea, and would have made them fun to play with. Just not sure how stable they would have been, given that they were so narrow.
Great summary Paul. I've never seen these toys either but they do look interesting. I have just taken possession of a tank toy myself, which I'll blog about soon.
Strange and beautiful toy!