cTIME ZONES VAST COUNTRY USA

 *cTime Zones Vast Country USA*

USA is spread over 80 degrees longitude : East to West 
 I degree longitude = 
  - 4 minutes time difference
  - 111 kms or 60 miles. 

Before the U.S. had time zones, how did people traveling across the country know what time it was ? 
    Until 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 12 miles in order to always have the correct time.
When people began traveling hundreds of miles in a day by train, calculating the time became a problem. Railroad lines needed to create *schedules* for departures and arrivals, but *every city had a different time* ! 

_*4 Standard Time Zones for Continental U.S. Introduced*_ 
     :    November 18, 1883    : 
At first the railroad managers tried to address the problem by establishing 100 different railroad time zones. With so many time zones, different railroad lines were sometimes on different time systems, and scheduling remained confusing and uncertain.

Finally, the railway managers agreed to use four time zones for the continental United States: *Eastern, Central, Mountain, and Pacific*. _Local times would no longer be used by the railroads_.   
 Difference between each 2 of the 4 adjacent Time Zones was kept as an hour : total time difference in zones located in extremity in the country is now 3 hours. 
  U.S. Naval Observatory, responsible for establishing the official time in United States, agreed to make the change. At 12 noon on November 18, 1883, the U.S. Naval Observatory began signaling the change. 

As Greenwich Mean Time (the official time used by U. S. Naval Observatory) was transmitted by telegraph, authorities in major cities and managers of the railroads reset their clocks.  
    All over the United States & Canada, people changed their clocks and watches to match the time for the zone they lived in. Quickly, the confusion caused by the many different standards of time was resolved.