North America Went From 140-Plus Local Times to Four Railroad Zones on 18 November 1883
On Sunday 18 November 1883 railroads reset their clocks at noon. A computed table shows how many minutes each city's morning moved, and which way.
In this article10 sections
“People will have to marry by railroad time and die by railroad time,” The Indianapolis Sentinel predicted when the railroads announced their plan. The Library of Congress law blog quotes the line in its history of standardized time.
On Sunday, 18 November 1883, at noon, North American railroads set their clocks to four zones centered on the 75th, 90th, 105th and 120th meridians west of Greenwich. The change replaced more than 140 local solar times and an estimated 80 railroad time standards (both figures from the Library of Congress). No legislature approved it. A convention of railroad officials did, and towns followed because the trains were already running on the new clocks.
How did people set a morning before 1883?
By the sun over their own town. Local mean solar time puts noon at the moment the sun crosses your meridian, and the Earth turns 15 degrees an hour, so every degree of longitude is worth four minutes. A town one degree west of its neighbor ran four minutes behind it, and nobody noticed until a train arrived.
Charles F. Dowd, who proposed regional zones in 1870, complained of “clocks at stations staring each other in the face defiant of harmony” (quoted by the Library of Congress). Inside a town the only requirement was that its clocks agreed with each other.
Who wrote the plan that replaced them?
Dowd’s 1870 pamphlet called for four zones one hour apart. Sir Sandford Fleming proposed a 24-hour world standard in his 1876 memoir Terrestrial Time. Cleveland Abbe wanted standard time for weather forecasting, which produced a Committee on Standard Time in 1879. William F. Allen, secretary of the General Time Convention and publisher of the Traveler’s Official Railway Guide, drew on all three and canvassed railroad officials for their opinions.
On 11 October 1883 the convention met at the Grand Pacific Hotel in Chicago, and a majority voted for Allen’s plan. Per the Library of Congress, the Naval Observatory and the Allegheny Observatory in Pittsburgh agreed to telegraph signals so that railroad clocks could be set together on the 18th.
What did the switch do to each city’s morning?
The table below is a calculation made for this article. It takes each city’s present-day longitude, compares it with the meridian of its zone, and multiplies the gap by four minutes per degree. Longitudes are rounded to hundredths of a degree, so corrections quoted in 1883 newspapers can differ by a few seconds.
| City | Longitude (°W) | Zone meridian (°W) | Clock moved |
|---|---|---|---|
| Boston | 71.06 | 75 | back 15.8 min |
| New York | 74.01 | 75 | back 4.0 min |
| Chicago | 87.63 | 90 | back 9.5 min |
| St. Louis | 90.20 | 90 | forward 0.8 min |
| Denver | 104.99 | 105 | under 1 min |
| San Francisco | 122.42 | 120 | forward 9.7 min |
| Pittsburgh | 79.99 | 75 | forward 20.0 min |
Pittsburgh is the outlier. It sits near 80°W but fell in the zone centered on 75°W, so a city that adopted railroad time had to jump twenty minutes ahead of the sun.
Why were there two noons?
Where clocks went back, the minutes of the shift came around twice. A bell that had struck noon at local time struck again when the telegraph signal said standard noon had arrived. That is the Day of Two Noons: a repeated midday in the east of each zone, and minutes lost at midday in the west.
The direction matters for anyone who rose by the clock. A Pittsburgh household that kept getting up at six woke twenty minutes earlier by the sun than it had the day before. A Boston household woke sixteen minutes later by the sun. Standard time moved no sunrise anywhere, but it changed how each morning related to one, and it did so for everybody in a town on the same Sunday. The same gap runs in the other direction today, which a separate table of eight places works out for the western edges of modern zones.
What is left of 1883 in an alarm app?
The rules. Every zone boundary and change is now a row in a database (the IANA tz database), and a phone alarm is stored as a wall-clock time plus a zone name that gets looked up again each day. Software that caches an offset instead misfires, as the technical FAQ on group alarms and daylight saving explains, and a scan of 24 clock changes shows which minutes vanish and which repeat.
Three loose ends
What did the Standard Time Act of 1918 add to the railroads’ zones?
It wrote standard time into federal law (40 Stat. 450), gave the Interstate Commerce Commission authority over zone boundaries, and created Daylight Saving Time, which was repealed after World War I. A year-round wartime version returned in 1942, and the Uniform Time Act of 1966, signed by President Lyndon B. Johnson, sought a uniform national approach.
Which observatories sent the noon signal in 1883?
The Library of Congress says the U.S. Naval Observatory and the Allegheny Observatory in Pittsburgh both agreed to telegraph a signal so railroad clocks could be set together. Other accounts credit the Allegheny Observatory alone, so the sources differ.
How can I work out how far my town’s clock sits from its sun?
Subtract your longitude from your zone’s central meridian and multiply the difference in degrees by four minutes. A town at 80°W in the Eastern zone (75°W) is five degrees west of the meridian, so the sun reaches it about 20 minutes after the clock’s noon.
What this article does not establish
The table shows what a city’s clocks would have moved if they matched the zone meridian exactly. It does not reconstruct which cities switched on the 18th, which waited, or what individual households did. The Library of Congress says most cities switched at once and others within a year, and this piece goes no further than that.
Source for the history: Library of Congress Law Library, “Whose Time Is It Anyway? A Brief History of Standardized Time Zones in the United States” (November 2024). The table is original arithmetic.