> [1883] ... a bunch of rich, white railroad tycoons met at a fancy Chicago hotel to agree on a standard timezone so their trains would work better together...

> [1883] ... a bunch of rich, white railroad tycoons met at a fancy Chicago hotel to agree on a standard timezone so their trains would work better together... The Brits did this for their railroad in 1847. Time balls were used to synchronise clocks before telegraph and radio. https://en.wikipedia.org/wiki/Time_ball https://en.wikipedia.org/wiki/Time_ball On clock accuracy, I was reading last night about time dilation due to gravity, and the difference in time rates from points less than one meter apart in height on earth have been experimentally verified.