![[Question] Metal Sign on Railroad Says "790Hz"](https://lemmy.radio/pictrs/image/9039ff9f-f299-4f9b-b752-6891f7ebd0be.jpeg){kind=link}
Dunno if this is actually radio related, but thought this community might know something about it.
I was walking down a stretch of railroad that I haven’t explored before when I happened across this metal sign nailed down to the tracks.
It’s pointing toward the nearest railroad crossing and says “790Hz”. Is this a radio frequency one could listen on and hear when the train is passing by? Or something else? I don’t know anything about trains
You should check out this patent. When the train goes over a special section of track, it will trigger the signal at the nearby crossing
790hz is the switching signal, as the contacts corrode the resistance increases so they have to be tested on a schedule.
Ahh, that makes sense. Thanks for the assist!