Today, we take it for granted that everyone in a region shares the same time. You check your phone, and it simply knows. But for most of history, every town kept its own clock, set by the Sun. Noon in one town could be a few minutes off from noon in the next. So why did the world finally agree to divide itself into time zones?
The short answer is trains. As railroads spread across the country, each town keeping its own local time became a confusing and even dangerous mess. In the United States and Canada, the railroads adopted standard time zones on November 18, 1883. Congress made them official in 1918.
When Every Town Had Its Own Noon
For thousands of years, people told time by the Sun. Solar noon is when the Sun is highest in the sky, and that moment shifts by about four minutes for every degree of longitude you travel east or west. When it was solar noon in London, it was still about 10 minutes before noon in Bristol, to the west.
That didn't matter much when the fastest way to travel was by horse. But once trains and telegraphs arrived, all those slightly different local times became a real headache.
Railroad Chaos
In 19th-century North America, each railroad ran on its own time, usually based on the local time of its headquarters or most important station. Train schedules were printed using that railroad's time. Some junctions served by several railroads had a separate clock for each one, all showing different times.
The confusion had serious consequences. A number of accidents happened when trains from different companies sharing the same tracks mistimed their passings. Something had to change.
The Day of Two Noons
Several people proposed solutions. Charles F. Dowd suggested time zones for the railroads around 1863, though the railroads never adopted his plan. Cleveland Abbe, chief meteorologist at the U.S. Weather Bureau, divided the country into four zones for his weather stations and pushed the railroads to adopt a similar system.
The version that finally won out came from William F. Allen, editor of the Traveler's Official Railway Guide. It started on Sunday, November 18, 1883, a date nicknamed "The Day of Two Noons." As standard noon arrived in each zone, railroad station clocks were reset to match.
The idea caught on fast. Within a year, about 85 percent of cities with more than 10,000 people were using standard time. Detroit was a stubborn exception and kept its own local time until 1900, then switched back and forth before finally settling on Eastern time. Congress made the zones official with the Standard Time Act on March 19, 1918.
Time Zones Go Global
Britain had already moved toward a single time years earlier. In 1840, the Great Western Railway began using Greenwich Mean Time, carried on portable clocks, and other British railways followed in what became known as railway time. In 1876, Scottish-born Canadian engineer Sir Sandford Fleming proposed dividing the whole world into 24 time zones.
Today, every country uses standard time, though not always neatly. China and India each use a single time zone even though they're wide enough for several. So the next time you set your watch after a trip, thank the railroads. Without them, you might still need a different clock for every town on the map.
