Regional Connector project makes milestone

5 June 2017

US – The TBM excavating twin tunnels for the Regional Connector project in Los Angeles broke through to the Grand Ave/Bunker Hills Station at 2nd/Hope Thursday morning, June 1.

Launched, last winter the TBM start mining in early February and in late April it completed digging through the Historic Broadway Station at 2nd and Broadway on its way to 2nd Place and Hope.

The Los Angeles County Metropolitan Transportation Authority said following the breakthrough, the TBM will be repositioned inside the station box area to continue tunnelling the remainder of the first tunnel to 4th Street and Flower. The TBM will then be taken apart and transported back to the 1st and Central Station site where it will be reassembled in order to begin mining the second tunnel.

The USD 1.75bn Regional Connector Transit Project is a 1.9-mile (3km) light-rail tunnel that will connect the Blue, Expo and Gold Lines in downtown Los Angeles and will include three new stations at 1st Street/Central Avenue, 2nd Street/ Broadway and 2nd Place/Hope Street. The project will reduce the need for light rail riders to transfer and speed up trips to and through the city.

When complete in 2021, the Connector tunnels will allow Metro to run one light rail line between Azusa and Long Beach. The other line will run between East Los Angeles and Santa Monica. The two lines will share five stations in DTLA: Pico, 7th/Metro and the three new underground stations being constructed as part of the Connector project.

The TBM was manufactured in Germany by Herrenknecht AG and is 21.6ft (6.9m) in diameter. It has advanced about 70ft (21.3m) per day on average. Completion of the twin 1.1-mile tunnels is expected in early 2018.