The Harbor Subdivision is a historic single-track main line of the BNSF Railway which stretches 26 miles (42 km) between rail yards near downtown Los Angeles and the ports of Los Angeles and Long Beach across southwestern Los Angeles County. It was the primary link between two of the world's busiest harbors and the transcontinental rail network. Mostly displaced with the April 15, 2002 opening of the more direct Alameda Corridor, the Harbor Sub takes a far more circuitous route from origin to destination, owing to its growth in segments over the decades. The subdivision was built in this fashion beginning in the early 1880s to serve the ports and the various businesses that developed along it.