It's an age old problem for railroads.
The Norfolk Southern line near me has “hot box detectors” about every 10 miles. Dragging equipment detectors less frequently. They automatically report milepost, track number, number of axles, and any defects via radio.
I remember sixty years ago when KCS trains would accidentally set the grass along the tracks on fire with sparks thrown from the wheels. We almost lost our house a few times from fires. It seems to be a lot less now as they do maintain the tracks much better.
Back in the day ALL railroad employees...stationmaster, section hands, crossing guards...were required to watch each passing train to be on the lookout for hotboxes.
More automation, fewer employees, less eyes on the boxes.
I agree, from the beginning I suspected that the bearings had seized up.