US and Canadian railroads adopt standard continental time zones

Background. Until 1883, each United States railroad chose its own time standards. As railroads were introduced, timetables had listed multiple arrival and departure times based on local time zones. The General Time Convention, an organization of US railroads charged with coordinating schedules and operating standards, became increasingly concerned that if the US government adopted a standard time scheme it would disadvantage its member railroads. Allen, the Convention's secretary, argued that North American railroads should adopt a five-zone standard, similar to the one in use today, to avoid government action.

Adoption. On October 11, 1883, heads of major railroads met in Chicago at the Grand Pacific Hotel and agreed to adopt Allen's proposed system. They determined that on Sunday, November 18, 1883, all United States and Canadian railroads would readjust their clocks to reflect the new five-zone system. This adjustment was triggered by a telegraph signal from the Allegheny Observatory in Pittsburgh at exactly noon on the 90th meridian.

Implementation. The system was inaugurated on Sunday, November 18, 1883, also called "The Day of Two Noons," when each railroad station clock was reset as standard-time noon was reached within each time zone. Most railroads adopted the new system as scheduled, though some did so early on October 7 and others late on December 2. The Intercolonial Railway, serving the Canadian maritime provinces of New Brunswick and Nova Scotia just east of Maine, decided not to adopt Intercolonial Time based on the 60th meridian west of Greenwich and instead adopted Eastern Time, so only four time zones were actually adopted by American and Canadian railroads in 1883.