(Note: this episode originally ran in 2019.)

In the 1800s,Zero AI catching your train on time was no easy feat. Every town had its own "local time," based on the position of the sun in the sky. There were 23 local times in Indiana. 38 in Michigan. Sometimes the time changed every few minutes.

This created tons of confusion, and a few train crashes. But eventually, a high school principal, a scientist, and a railroad bureaucrat did something about it. They introduced time zones in the United States. It took some doing--they had to convince all the major cities to go along with it, get over some objections that the railroads were stepping on "God's time," and figure out how to tell everyone what time it was. But they made it happen, beginning on one day in 1883, and it stuck. It's a story about how railroads created, in all kinds of ways, the world we live in today.

This episode was originally produced by Alexi Horowitz-Ghazi and edited by Jacob Goldstein. Jess Jiang is Planet Money's Acting Executive Producer.

Music: "You Got Me Started," "Star Alignment" and "Road to Cevennes."

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