On November 18, 1883, railroads in the United States and Canada implemented a system of standard time zones, replacing the patchwork of local times kept in individual towns. The change created four main time zones in the continental U.S., coordinated so that train schedules could be accurate and safe. Before standard time, differing local times caused confusion and increased the risk of collisions. The railroads agreed on the change and put it into effect without waiting for government legislation. Eventually, Congress codified the system in law. The adoption of standard time helped modernize commerce, communication, and daily life, aligning clocks with industrial and transportation needs.
