The San Diegan was one of the named passenger trains of the Atchison, Topeka and Santa Fe Railway, and a “workhorse” of the railroad. Its 126-mile (203-kilometer) route ran from Los Angeles, California south to San Diego. It was assigned train Nos. 70–79 (Nos. 80–83 were added in 1952 when RDCs began operating on the line). Amtrak continued to operate the San Diegan when it took over operation of the nation's passenger service on May 1, 1971. After extending the route to the Central Coast in the 1980s and 1990s, Amtrak rebranded the route as the Pacific Surfliner on June 1, 2000.