A streetcar is a vehicle that carries passengers along city streets on metal rails, powered by electricity from overhead wires. Picture a bus that can't steer left or right because it follows tracks built into the road, moving smoothly through neighborhoods while picking up and dropping off riders.

Streetcars were extremely common in American cities from the 1880s through the 1940s. They shaped how cities grew, because neighborhoods sprang up along streetcar lines, letting people live farther from where they worked. The familiar clang clang of the streetcar bell warned pedestrians and drivers to clear the tracks.

Most American cities removed their streetcar systems in the 1950s and 1960s, replacing them with buses and encouraging automobile use. However, some cities like New Orleans and San Francisco kept their historic streetcars running, and others have built modern versions called light rail. In many places, the word “trolley” is used for the same kind of vehicle, though people in different parts of the country prefer one term over the other.

You might know streetcars from the classic play A Streetcar Named Desire or from pictures of old-fashioned city streets. Today, when city planners talk about building streetcar systems again, they're trying to recreate that reliable, pleasant way of moving people around without everyone needing a car.