One of my classmates in elementary school lived close to a closed factory. The backyard with lot of scrap was a wonderful adventurous playground. The city train station was further down the street and the trains passed just behind the fence furthest in the back. When someone heard a train approaching he would yell "Train's coming!". Whatever play would cease immediately and we all ran to pick up one of our poops on a stick and line up at the fence. Great was the joy when one of us hit a window.