The San Diego Electric Railway (SDERy) was a mass transit system in Southern California using streetcars and (in later years) buses. The SDERy was established by "sugar heir," developer, and entrepreneur John D. Spreckels in 1892. The railroad's original network consisted of 5 routes, delineated as follows:
The company would establish additional operating divisions as traffic demands led to the formation of new lines. The company also engaged in limited freight handling primarily as an interchange with Spreckels' San Diego and Arizona Railway (SD&A) from 1923 to 1929.
At its peak, the SDERy's routes would operate throughout the greater San Diego area over some 165 miles (266 kilometers) of track. Steadily-declining ridership, due in large part to the phenomenal rise in popularity of the automobile, ultimately led the company to discontinue all streetcar service in favor of bus routes in 1949. The demise of some streetcar companies in the United States has been tied by some to the alleged General Motors streetcar conspiracy, in which a consortium of General Motors, Standard Oil, and others formed a front company, National City Lines, in order to buy streetcar lines, shut them down, and replace them with buses. The plot of Touchstone Pictures' 1988 film Who Framed Roger Rabbit is loosely based on this theory.
The few surviving pieces of rolling stock are on display at the Pacific Southwest Railway Museum in Campo, the San Diego Electric Railway Association in National City, and the Orange Empire Railway Museum in Perris, California.