Infrared scanners beside the rails read the temperature of every bearing as a train passes, and the detector then announces the result on the road channel in a recorded voice, usually its milepost, the axle count and no defects. Many units also check for dragging equipment, and when one finds a defect it calls out the axle number counted from the head end, and the train must stop for an inspection. Busy main lines carry a string of them, and crews refer to each one by milepost or place name.
Hot box detector at 312.6 called a hot journal on axle 214, so we're stopping to look at it.
Silence is a message too: when a detector fails to announce, the crew reports it and follows the railroad's rules for an inoperative detector.
Also heard as
- HBD
- defect detector
- detector
- talker
Related terms
Hot box
An overheated wheel bearing on a railcar, a defect that can burn the end off an axle if missed.
MP
Milepost: the numbered marker that fixes every location on a railroad by distance along the line.
Bad order
A car or locomotive with a defect that keeps it from running until it is repaired.
Set out
To leave a car or group of cars on a track short of the train's final destination.