The Pacific Southwest Railway Museum preserves Southern California railroad history at sites in Campo and La Mesa along historic railway lines. Since 1986, its volunteer-run Campo campus has operated excursion trains from a restored 1916 depot, maintained about 140 acres, and displayed around 90 locomotives and railcars, including steam, diesel, and other rolling stock. Exhibits include preserved equipment, railroad signaling, and the Southwest Railway Library, which holds California’s second-largest collection of railroad history materials. In La Mesa, the museum manages the town’s original depot, the oldest building in the city and the only surviving station from the San Diego and Cuyamaca Railway, alongside a small display train.