The first public transportation system in Portland, Oregon, began in 1872 as a horsecar line on First Street. When, in 1891, the separate cities of East Portland and Albina joined Portland to form a single city of 88,200 people, the City & Suburban Railway Company merged out of the Willamette Bridge Railway Company and the old Third Street horsecar system. Most of the remaining street railways joined into the Portland Consolidated Street Railway Company. In 1893, the East Side Railway Company gave service between Portland and Oregon City. Around 1907 this entire system of streetcar lines, along with interurban lines and power companies, merged into a single company - Portland Railway, Light and Power Company, which became Portland Electric Power Company in 1924. The high point for electric streetcars was around 1912. Following World War I, streetcar companies competed with the auto. Trolley buses were introduced in 1936. Interurban passenger service ended in 1958.
From the guide to the Portland, Oregon, Streetcar Blueprints and Drawings, 1890-1943, (Oregon Historical Society)