On November 18, 1883, four standard time zones for the continental U.S.A. were introduced at the instigation of the railroads. At noon on this day the U.S. Naval Observatory changed its telegraphic signals to correspond to the change. Until the invention of the railway, it took such a long time to get from one place to another that local “sun time” could be used. When traveling to the east or to the west, a person would have to change his or her watch by one minute every twelve miles.
…At twelve o’clock noon on November 18, 1883, as Greenwich Mean Time (GMT) was transmitted, the U.S. Naval Observatory began signaling the new time standard. Authorities in major cities and managers of the railroad reset their clocks. All over the United States and Canada, people changed their clocks and watches in synchronization with their zone’s standard time. In one moment the many different standards of time that had caused conflict and confusion, were resolved into four simple standards.
Don’t let Arizonans read about this “sun time” thing; surely they’d want to reinstate it.