Sanford Fleming, who, from 1867 until he retired in 1880, was chief engineer for the dominion government, was regarded as Canada's foremost railway engineer. By the time he was 70 years old, he had surveyed the country from Ottawa to Vancouver and helped to build thousands of miles of railway track. Based on Sanford Fleming's ideas, delegates from 27 nations met in Washington, DC, in 1884 and agreed on a system which is basically the same as the one which is still in use. Pacific Standard Time, Mountain Standard Time, Central Standard Time, Eastern Standard Time, Atlantic Standard Time, and Newfoundland Standard Time. The boundaries of each zone are not strictly defined on the basis of size, but each zone is approximately 15 degrees apart.
Boundaries vary somewhat to conform to local geographical and political regions.
In addition, if daylight saving time is in effect, one hour less must be subtracted for locations west of Greenwich and one hour more, added for areas east of Greenwich. Center of Time 6.