A Line (Los Angeles Metro)
The A Line (formerly, from 1990 to 2019, and colloquially known as the Blue Line)[3][4] is a 48.5-mile (78.1 km) light rail line in Los Angeles County, California. It is one of the six lines of the Los Angeles Metro Rail system, operated by the Los Angeles County Metropolitan Transportation Authority (Metro). The A Line serves 44 stations and runs east-west between Azusa and Pasadena, then north-south between Pasadena and Long Beach. It interlines and shares five stations with the E Line in Downtown Los Angeles. Service operates for approximately 19 hours with headways of up to 8 minutes during peak hours. The A Line is currently the longest light rail line in the world.
A Line
Blue Line (1990–2019)
Gold Line/L Line (north of Little Tokyo/Arts District)
801
44 (4 more under construction)
Division 11 (Long Beach)
Division 24 (Monrovia)
Kinki Sharyo P3010 or AnsaldoBreda P2550 running in 2- or 3-car consists
60,423 (weekday, October 2023) 
[1]
15,069,823 (2023) 41.3%
July 14, 1990
48.5 mi (78.1 km)[2]
2 (except single track Long Beach loop)
Mostly at-grade in private right-of-way, with some street-running, elevated and underground sections
4 ft 8+1⁄2 in (1,435 mm) standard gauge
55 mph (89 km/h) (max.)
24 mph (39 km/h) (avg.)
The A Line is the oldest and busiest light rail line in the Los Angeles Metro Rail system, carrying an average of 60,423 riders on weekdays in October 2023. Its initial segment from Long Beach to Downtown Los Angeles opened in 1990, using much of the original right-of-way of the Long Beach Line, a former Pacific Electric interurban line. The line became heavily used, prompting the implementation of capacity and reliability improvements throughout its alignment. A plan to extend the line north to Pasadena in the San Gabriel Valley surfaced in the 1980s but was canceled due to funding constraints. The Gold Line (renamed the L Line in 2020) light rail line opened in 2003, completing part of the planned extension from Union Station to Pasadena. It was extended east to Azusa in 2016.
The northern extension was revived as part of the Regional Connector project in the early 2000s, and construction began in 2014. The project enabled A Line trains to run to the San Gabriel Valley via a new downtown tunnel connecting the A Line tracks to the L Line tracks. The A Line's current Azusa–Long Beach service was introduced in June 2023 with the opening of the Regional Connector, incorporating the Union Station–Pasadena–Azusa portion of the former L Line. Construction is underway to extend the A Line further east to Pomona and Montclair.