The very first streetcar riders lived in New York City in 1832. They weren’t riding in fancy electric-powered pods, though. They were riding behind horses in box-like cars. These ran along tracks in the city streets. What was the point of riding in a horsecar when you could just ride in a horse-drawn coach instead?

The answer can be summed up in one word: friction. Imagine you are pushing a toy racecar along a smooth tabletop. Then you start pushing it through a sandbox. On the table, the car moves easily. But in the sandbox, sand and little rocks get in the way of the wheels, creating resistance called friction. The same thing happened when horse carriages moved in the streets. But when carts were fitted perfectly to tracks, friction was taken away. The carts moved smoothly. Horses could pull heavier loads with a lot less work.

Horsecarts were helpful. But they were also messy. People had to be hired just to pick up the horse poo! The carts, though they moved smoothly, didn’t go very fast—just about the pace of a quick walk. Soon people were ready for the next invention: the cable car.

Cable cars showed up in many cities soon after the U.S. Civil War. The cars were attached to underground cables that moved all the time. But they weren’t perfect either. It cost a lot of money to build them. On top of that, they only had one speed. But what about when you go around sharp corners? You need to slow down! Cable cars couldn’t. That made them dangerous.

In the late 1880s, people made a discovery. Streetcar lines could run using electricity! Soon, people all over the United States traveled on electric streetcars, or trolleys—the same way people in Kansas City do now.