L.A.’s D Line Extension Marks Milestone

The Los Angeles County Metropolitan Transportation Authority (Metro) announced on April 2 that it has successfully completed tunneling for the D Line Subway Extension Project that will connect downtown L.A. with West L.A.

This major construction milestone was accomplished safely in one of the densest and most geologically challenging urban corridors in the L.A. region and nation.

“This safe completion of tunneling through this part of Los Angeles is a milestone in Metro’s work to expand fast and reliable public transit across the region,” said Karen Bass, L.A. City Mayor and Metro Board Chair. “When completed, the D Line extension will make Metro transit available to 53,300 more weekday riders traveling between Downtown Los Angeles and the Westside. Thank you to all of the construction workers who have given their time and talent to successfully complete the tunneling.”

With the completion of tunneling, Metro will continue to work with its two contractors as a part of a joint venture with Skanska-Traylor-Shea and Tutor-Perini/O&G to complete seven new underground stations in Section 1 between Wilshire/Western and Wilshire/La Cienega, Section 2 between Wilshire/La Cienega and Century City, and Section 3 between Century City and Westwood.

Contractors utilized the latest tunnel boring machine (TBM) technology to excavate approximately 40-60 ft per day to help complete tunneling for the project.

During its five years of tunneling, Metro faced and successfully overcame many technical challenges like gassy ground, tar sands and abandoned oil wells. Near the La Brea Tarpits, for example, Metro’s advanced TBMs made their way through tar sands, and used horizontal directional drillings to probe the earth so contractors could identify and remove potential objects before any TBM damage occurred. Metro also safely used the same methods to identify and avoid unmapped and abandoned oil wells underneath Beverly Hills High School.

“Now that tunneling is complete, it won’t be long before Metro completes this mega-project and makes it possible for everyone to travel from downtown L.A. to West L.A. in under 30 minutes,” said Katy Yaroslavsky, L.A. City Council Member and Metro Board Member. “This subway extension will catalyze ridership on the entire Metro System in the years ahead, bringing many thousands of new riders throughout Metro’s transit system.”

Forecasted openings are 2025 for Section 1, 2026 for Section 2 and 2027 for Section 3 of the project.
Other projects celebrated recent milestones too. In Rhode Island, the Narragansett Bay Commission (NBC) has completed the excavation and lining of the 2.2-mile long, 30-ft diameter Pawtucket Tunnel. The project is Phase III of NBC’s Combined Sewer Overflow (CSO) Abatement Program, known comprehensively as RestoredWaters RI. The $245 million project is being built by a joint venture of CBNA and Barletta under a design-build contract.

In Virginia, AlexRenew announced the completion of its 2.2 mile long, 12-ft diameter RiverRenew Tunnel that will reduce overflows into the Potomac River. Traylor-Shea was awarded a $454.4 million contract to complete the final design and construct the tunnel.

Jim Rush, Editor/Publisher, TBM

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