Norfolk Southern Defect Detector Critical Alarm Hotbox Messages

The NS defect detector at milepost 337.8 in Huntsville, Alabama was malfunction this morning, giving trains false hotbox alarms. These were for container train 23N. A hotbox is a hot bearing. A failing bearing gets hot, giving some warning before it fails. Bearing failure normally caused a derailment. The term hotbox dates back to old plain (journal) bearings that had a compartment that had to be packed with lubricant, but the term is still used with modern roller bearings. This was recorded on the road channel here, MHz or AAR channel 49. The radio used here is a Yaesu FT-7900R amateur transceiver, receive-only on this frequency. March 16, 2021