a yellow circle on a red metal surface

This is from the side of an old train in Texas. I was walking by and saw this circle and picked up my camera and snapped a few shots trying to make sure everything was symmetrical, it was the middle of August and I was pouring sweat and took this handheld. My lens, the Sigma 24-70mm ART is extremely heavy so when I thumbed through and saw this shot, I was extremely pleased with the outcome!