The Invention of Standard Time

Until the late nineteenth century, most towns set their clocks by the sun. When the sun reached its highest point in the sky, it was noon, and because the sun reaches that point at different moments in different places, every town kept its own local time. A traveler moving east or west might have to adjust a watch several times in a single day.

For most of history, this system caused few problems, since people rarely traveled far or fast. The spread of railroads changed that. Each railroad company scheduled its trains according to the local time of its home city, so a single station might display several clocks showing different times. Passengers found the schedules confusing, and the lack of a common standard contributed to missed connections and, occasionally, to accidents.

In 1883, railroads in the United States and Canada adopted a system of standard time zones. Within each zone, every clock showed the same time, and the time changed by exactly one hour from one zone to the next. The public adapted quickly, although some cities initially resisted what they saw as “railroad time.” The United States did not make the zones official law until 1918, long after most people had come to rely on them.