Which supporting detail from the passage would be most important to include in a summary?
Until the 1800s, there was no such thing as standard time. Each local
town had its own time, based on the position of the sun over the town.
Times often differed between towns that were only a short distance
apart. In the United States, for instance, there were over 300 different
time systems
Why did this change? Railroads. With so many different times, it was
impossible for people to know when to catch the train Accidents even
resulted sometimes, when operators of trains using the same track
had different times on their clocks. So, to make train travel possible,
the world was divided into time zones, and times were standardized