The San Joaquin operates 14 trains (7 in each direction) each day between Bakersfield and Stockton. From Stockton, five trains from Bakersfield continue west to Oakland, while two trains proceed north to the state capital of Sacramento. Central Valley communities served include Fresno, Corcoran, Hanford, Lodi, Madera, Merced, Modesto, Turlock/Denair and Wasco. Delta/Bay communities of Antioch, Martinez, and Richmond are also served by the San Joaquin. Los Angeles is not served on this route due to the bottleneck of the Tehachapi Pass line, where the Union Pacific prohibits passenger train use due to freight traffic along the world's busiest single-track railway. (On rare occasions Amtrak trains use this as a detour if their railway tracks are being repaired.) The San Joaquin has operated since 1974.