In the United States a street running light rail car is often called a trolley or streetcar. And Europe they are called trams, so there is no difference.

In the context of modern urban transit, the terms "tram" and "trolley car" are often used interchangeably, but they possess high-fidelity historical and regional distinctions. A tram (or streetcar) refers to a rail vehicle that runs on tracks embedded in public streets. The term "tram" is the standard in British English and most of Europe. A trolley car specifically refers to a vehicle powered by an external electric source via a "trolley pole" that touches an overhead wire. While most vintage streetcars were technically trolley cars, not all trolleys are on rails; for instance, a "trolleybus" uses rubber tires but still relies on overhead wires. In the US, "trolley" is also frequently used to describe tourist buses styled to look like vintage streetcars. In 2026, the distinction has largely blurred into the category of "Light Rail," which describes high-capacity, high-tech versions of these traditional systems that often operate in their own dedicated lanes to avoid traffic while maintaining the nostalgic aesthetic of the early 20th-century urban commute.