I’ve noticed that in Mundelein on the Metra North Central Line there are flashing X’s at every grade crossing for the RR engineer. I’ve never seen these anywhere else. What are they called and why are they there?
The “X” indicates to locomotive engineers that the automated crossing bells are working and (if they are indeed working as indicated by the “X” visible to the engineer) he/she should NOT blow his/her horn at that crossing.
Mundelein is a quiet zone, made possible by electronic horns at the grade crossings. The flashing Xs inform approaching train crews that the horns are functional, and they may go through without sounding their own horns. If the Xs are not lit, they’d have to sound their horns.