Los Angeles Regional Connector

The Los Angeles Regional Connector is a 1.9-mile rail alignment that includes a tunnel that will link three light rail transit lines and the city’s heavy rail subway when it is completed in 2021.

Digging for the first half of the 1.1-mile tunnel concluded on July 19, 2017 when the tunnel boring machine (TBM) – known as “Angeli” – broke through to a reception pit at 4th and South Flower streets in the city’s downtown. Angeli was taken back to the original starting point at 1st Street and Alameda in Little Tokyo to continue digging a parallel tunnel, which is expected to be completed by early 2018.

The Los Angeles County Metropolitan Transportation Authority’s $1.75 billion Regional Connector project will extend from the Little Tokyo/Arts District Station of the Gold line light rail to the 7th Street/Metro Center Station in downtown Los Angeles, allowing passengers to bypass Union Station and transfer to the Blue, Expo, Red and Purple lines. When completed, passengers will be able to travel from Azusa to Long Beach, or from East Los Angeles to Santa Monica, without transferring trains.

WSP USA has worked on the Regional Connector project since 2008, providing planning, environmental and engineering services, as well as construction engineering support. WSP will continue to provide design support services as the project works toward revenue operations, scheduled to begin by December 2021.

Stakeholders that will benefit from this extension include several major Los Angeles cultural institutions, including the Walt Disney Concert Hall, the Colburn School of Music and The Broad art museum.

The project includes the creation of three new stations – Little Tokyo/Arts District Station at 1st Street and Central Avenue, Historic Broadway Station at 2nd Street and Broadway, and Grand Avenue Arts/Bunker Hill Station at 2nd Street and Hope Street.

The Regional Connector tunnel includes some “firsts” for Los Angeles. It is the first cavern excavated in weak rock in Los Angeles for a rail crossover that will be constructed using the sequential excavation method of tunneling.

It will also be the first time that Los Angeles transit will use high-speed elevators instead of escalators. Located approximately 100 feet below the surface, the station at 2nd Street and Hope Street will have six high-speed elevators with the hoisting equipment below the elevators, not above, to avoid the visual impact at the station entrance pavilion.

One of the project’s innovations involved the location of the fan plant that will provide ventilation for the new tunnel at the junction of the two lines coming into Little Tokyo. Rather than backfill the TBM launch pit when digging concludes, the fan plant will now be installed in this location, thus avoiding additional excavation and resulting in significant cost savings for the client.

Meeting the commitments made for mitigation of environmental impacts, particularly in the Little Tokyo neighborhood, posed challenges that kept the designers on their toes. Noise and vibration impacts of rail operations required extensive efforts to properly establish design-build performance requirements, and to work with the stakeholders and the final designer to ensure mitigation is achieved.

Connecting two existing transit lines that use systems equipment of different designs and ages also requires careful planning that requires expertise and experience in rail transit systems. While the path is complicated, what was set in motion years ago is happening, and once the tunneling is completed and the underground stations are concreted, WSP will turn its attention to the transit systems. WSP staff will be involved in the process of rail activation and will provide technical assistance after start of operations.