Yes I have had hot bearings, Axle Boxes. There is Detectors line side but not everywhere.
When on Double track or in a crossing loop we just do quick inspections from the cab as the train rolls past, any problems, smoke are reported to the crew via radio.
If you have a hotbox (term for hot axlebox) normal practice is to stop, go have a look, contact control & inform them of the problem, make a decision on the wagon, you may be able to tow it at low speed to the next loop, siding where you can remove it from the train or it may be a complete cripple & need someone to come out & jack it up & repair it or fit it with poney wheels to allow it to be towed.
I have had one Axle completly shear inhalf!
, a chain sitting on the end of a wheat hopper feel down onto the bogie frame while the train was moving & caught around the front of the bogie with the end on the axle, the heat & cutting action of the chain cut the axle inhalf
, wouldnt have happened if the previous crew we relieved had of removed the piece of chain or tied it up.