Some people may remember yellow and white dots on freight cars, applied in the late 1970's, to identify whether or not the car had a certain type of wheel suspected of causing derailments. Specifically, the wheels were 33" U-1 wheels manufactured by a company in the southeast. The wheels were reported to crack and disintegrate. Cars with yellow dots had been inspected and found to not have those wheels. Cars with white dots had the wheels and the wheels had to be replaced by a certain date. I do remember, when the wheels were removed, a hole was immediately burned into the wheel so it could not be mistakenly reused. The wheel pictured in the photo was reported to be one of those wheels, on a SCL boxcar, that caused a derailment on the RF&P at Brooke, VA on Sept. 24, 1976. Amazingly, the car made it over eight miles after the wheel began to fail.