[3] Passenger and freight services by steam locomotives began on September 26, 1835, originally without a dedicated right-of-way (it ran on public streets), although one was eventually established in the neutral ground (the median).

Service began as a suburban railroad, since Carrollton was at that time a separate city, while areas along the route were still mostly undeveloped.

[4][5] As the area along the line became more urbanized, objections to the soot and noise produced by the locomotives increased, and transport was switched to cars that were powered by horses and mules.

[3] For decades in the late 19th century, desire for a mode of transit more swift and powerful than horses but without the disruptive effects of locomotives resulted in a number of systems being tried out.

Experimental systems included overhead cable propulsion (with a cable clamp patented by P. G. T. Beauregard in 1869 later being adapted for the San Francisco cable car system), and several innovative designs by Dr. Emile Lamm, including ammonia engines, a "Chloride of Calcium Engine", and most successfully Lamm Fireless Engine which not only propelled pairs of cars along the line in the 1880s but was adopted by the street railways of Paris.

In 1950, plans were made to fill in the New Basin Canal, which the Belt Lines crossed on a bridge on Carrollton Avenue.

But it is not possible to provide the historic cars with wheelchair access doors and lifts in compliance with the Americans with Disabilities Act (ADA).

This recognizes it as a place that possesses "exceptional value and quality in illustrating or interpreting the heritage of the United States," quoting the announcement from the Department of the Interior.

[7] It joins the San Francisco cable car system as one of only two moving streetcar National Historic Landmarks.

At least one wheelchair lift-equipped car was to be added to the line, but the historic Perley Thomas streetcars were not to be modified.

[11][12] In May 2024, the Federal Transit Administration awarded RTA $5.5 million to construct additional accessible platforms on the line.

[15] The principal equipment of the line consists of 35 streetcars built in 1923–24 by the Perley A. Thomas Car Works.