BNSF (Burlington Northern Santa Fe Railway) and Union Pacific Railroad both have railway lines in the Central Valley. The BNSF Bakersfield Subdivision runs from Bakersfield to Calwa, four miles (6 km) south of Fresno. From Calwa the BNSF Stockton Subdivision continues to Port Chicago, west of Antioch. The Union Pacific Railroad Martinez Subdivision runs from Port Chicago through Martinez, Richmond and Emeryville to Oakland. The UP's Fresno Subdivision runs from Stockton to Bakersfield. Traffic passes through a large, historical yard in Roseville before heading north to Oregon or east to Nevada. Amtrak operates six daily "San Joaquins" trains over these lines.