It was told to me years ago that the Temperature was given by the Detectors to assist everyone (Dispatchers, Train Crews, Signal Dept., Maintenance of Way) in many ways, too much to expalin here. Maintainers have told me that there are glitches in some detectors and that is why the Temperature is sometimes way off. Some detectors don't even give a temperature, and a maintainter told me that if the temperature always given is way off and is difficult to correct, then they set up the Detector to not give a temperature reading. Hope this is helpful.