Prior to the late nineteenth century, time keeping was a purely local phenomenon. Each town would set their clocks to noon when the sun reached its zenith each day. A clockmaker or town clock would be the “official” time and the citizens would set their pocket watches and clocks to the time of the town. Enterprising citizens would offer their services as mobile clock setters, carrying a watch with the accurate time to adjust the clocks in customer’s homes on a weekly basis. Travel between cities meant having to change one’s pocket watch upon arrival.

However, once railroads began to operate and move people rapidly across great distances, time became much more critical. In the early years of the railroads, the schedules were very confusing because each stop was based on a different local time. The standardization of time was essential to efficient operation of railroads.

Today, many countries operate on variations of the time zones proposed by Sir Fleming. All of China (which should span five time zones) uses a single time zone — eight hours ahead of Coordinated Universal Time (known by the abbreviation UTC, based on the time zone running through Greenwich at 0 degrees longitude). Australia uses three time zones — its central time zone is a half-hour ahead of its designated time zone. Several countries in the Middle East and South Asia also utilize half-hour time zones.

Since time zones are based on segments of longitude and lines of longitude narrow at the poles, scientists working at the North and South Poles simply use UTC time. Otherwise, Antarctica would be divided into 24 very thin time zones!

The time zones of the United States are standardized by Congress and although the lines were drawn to avoid populated areas, sometimes they’ve been moved to avoid complication. There are nine time zones in the U.S. and its territories, they include Eastern, Central, Mountain, Pacific, Alaska, Hawaii-Aleutian, Samoa, Wake Island, and Guam.

With the growth of the Internet and global communication and commerce, some have advocated a new worldwide time system.

American railroads maintained many different time zones during the late 1800s. Each train station set its own clock making it difficult to coordinate train schedules and confusing passengers. Time calculation became a serious problem for people traveling by train (sometimes hundreds of miles in a day), according to the Library of Congress. Every city in the United States used a different time standard, so there were more than 300 local sun-times to choose from. Railroad managers tried to address the problem by establishing 100 railroad time zones, but this was only a partial solution to the problem.

Operators of the new railroad lines needed a new time plan that would offer a uniform train schedule for departures and arrivals. Four standard time zones for the continental United States were introduced on November 18, 1883.

Time Zones were created to synchronize time all across the world. Believe it or not, until about the 19th century there were no central time standards. Every town, city or location kept their own time and usually stayed in sync thanks to a clock tower or large clock placed somewhere accessible to all.

Many different tools were used to measure time, including the pendulum clock which was first created in the 17th century. People still used the sun, as it rose and set, to measure the time of day.

However, in 1764 John Harrison — an English horologist — made a big discovery. He realized that clocks could be used to discern the location of a ship at sea. Even better, he realized it could be done much more accurately than any current measurements they were using at the time. Thanks to his discovery the Act 5 George III — or the Longitude Act — was adopted to draw up the concept of longitude we still use today.

Although this addressed some issues regarding time and made it easier to locate ships out at sea, many places around the world continued to use the sun’s movements as their standard for timekeeping. As you can imagine, this caused quite a bit of fuss when railways were adopted and telecommunications became popular.

American railroads, in particular, ran into a lot of issues in the 1800s, as each train station operated independently — all of them used their own time standard. It’s not difficult to understand why this would be a problem, especially considering trains were meant to run on a schedule and both depart and arrive at specific times.