The Regional Connector Transit Project constructed a 1.9-mile (3.1 km) light rail tunnel for the Los Angeles Metro Rail system in Downtown Los Angeles. It connected the A and E lines with the former L Line. The A and E lines previously both terminated at 7th Street/Metro Center station, coming from Long Beach and Santa Monica, respectively, while the L Line ran through Little Tokyo/Arts District to either Azusa or East Los Angeles. Now the A and E lines continue together through new stations at Grand Avenue Arts/Bunker Hill, Historic Broadway, and Little Tokyo/Arts District. From there, they diverge on the former L Line toward Azusa and East Los Angeles, respectively. The project provides a one-seat ride into the core of Downtown for passengers on those lines who previously needed to transfer, thus reducing or altogether eliminating many transfers of passengers traveling across the region via Downtown Los Angeles.

The Los Angeles Metro Rail is an urban rail transit system serving Los Angeles County, California in the United States. It consists of six lines: four light rail lines and two rapid transit lines, serving a total of 101 stations. It connects with the Metro Busway bus rapid transit system, the Metrolink commuter rail system, as well as several Amtrak lines. Metro Rail is owned and operated by the Los Angeles County Metropolitan Transportation Authority (Metro).