Gee maybe mounting parasols and fans into the transformers to reflect the sunlight and to cool the transformers might work. Hell put a big fan in the transformers to remove the heat like a computer power supply and put reflective parasols on top to stop direct sunlight heating them up more. Sounds common sense but they would rather replace than fix the problem. I bet the ones failing are at capacity also and putting a larger capacity one like double would cost to much in bonus money.