Talk:Grade crossing predictor

Audio Frequency Overlay
There also audio frequency overlay systems in use. If my understanding is correct, they measure the return time of pulses of AC currect applied to the rails. LorenzoB (talk) 23:44, 26 October 2008 (UTC)

Electrification and Junctions
Predictor circuits are not necessarily suitable where there is AC or DC electrification. This would not generally be a problem in the US were most lines are not electrified.

Also, predictors are not necessarily suitable where there a need for complicated track circuits over turnouts and junctions. Tabletop (talk) 04:31, 22 September 2011 (UTC)