Reading Comprehension

Read the passage and answer the question.

In the nineteenth century, many cities adopted standardized time only after railways made the old patchwork of local clocks impractical. Before then, each town set its clocks by the sun, so noon in one place might differ by many minutes from noon in a town just down the line. This caused confusion in printing train schedules and even led to accidents when trains running on different local times shared the same track. Eventually, railway companies imposed a single uniform time across their networks, and governments later formalized these zones into the system used today.