Los Angeles Metro's A Line runs 57.6 miles (92.7 km) between Pomona and Downtown Long Beach, serving 48 stations, making it the world's longest modern light rail line. It is comprised of the old Blue Line, operating from Long Beach to downtown Los Angeles, combined with about half of the old Gold Line that ran from downtown Los Angeles to Azusa. After reconfiguring these lines to make them more efficient in 2019 and 2020, the lines were renamed with letters rather than colors. The A Line, already lengthy, was extended further east to Pomona in late 2025.
The A Line runs east–west between Pomona and Pasadena, then north-south between Pasadena and Long Beach. In Downtown Los Angeles it interlines with the E Line, sharing five stations. Service operates about 19 hours daily with headways as short as 8 minutes during peak hours. It is the busiest light rail route in the system, carrying over 22 million riders in 2024 and averaging 69,216 weekday boardings in May 2024.
LAMTA P3010 1112, one of a group of light rail vehicles constructed by Kinki Sharyo between 2014 and 2020, has departed Chinatown and is rounding the elevated trackage that takes it into Los Angeles Union Station. (Los Angeles, California - October 31, 2025)
