Loving the “ballparks of youth!” meme; here are mine. (See also brian-k, Drew, El Mighty Flynn, and Ben.)
I played, never very well, on all four of the dusty diamonds you see in the first picture. The second picture, taken from the two-lane road that runs through the right hand side of the first picture, illustrates that it’s a sloping viaduct that crosses some nearby train tracks. Legend has it that only a few kids ever hit home runs “over the road,” but I was never there to see it happen.