Q. About Donner Pass Reno whistles

Upon entering Reno, railway signs read "X" when approaching highway grade crossings. In most routes it is a "W" that means sound your whistle. In other routes it sometimes reads "W/X" which I interpret as meaning to sound the whistle for multipul grade crossings ahead. Quite zones are a "W" with a red circle and a red slash through it. So in Reno, does the "X" mean quite zone? I ask this because I cannot believe that all the casinos and other trackside businesses would put up with train horns blasting all the time. What does that "X" actually mean? Nothing in manual about it.

