12,000 horsepower is at work as a quartet of four-year-old Cotton Belt GP40-2s, led by SSW 7657, kicks up dust as they pull a piggyback train through City of Industry, California, on April 1st, 1983. This eastbound is passing one of SP's iconic hotbox detectors which, in the event of a hotbox (an overheating truck journal) would display the axle number in lights after the train passed, so that the crew in the caboose would know which axle to check.
