Tunnel boring machine completes its job on Regional Connector project

And that’s all she wrote. On Tuesday evening, the tunnel boring machine (TBM) for the Regional Connector — named Angeli — arrived beneath the intersection of Flower and 4th streets in downtown Los Angeles, thereby completing the part of the work requiring a TBM. 

Work on the second of two tunnels began last September in Little Tokyo and progressed at a swift pace. It only took four months to complete the 1.1-mile long tunnel, moving forward about 70 feet a week on average. There was one week, however, in which the TBM was able to dig 190 feet.

About 1,160 concrete rings to support the tunnel were installed as part of the work.

The Regional Connector is a pair of 1.9-mile light rail tunnels that will tie together the Blue, Expo and Gold Lines, allowing for much quicker rail travel to and through downtown L.A.

Crews must now complete building the tunnel box under Flower Street between 4th and 6th streets. The next major phase of construction will be to build the road decking at the 6th and Flower intersection while continuing to excavate below the surface.

In order to extract the TBM from below ground, a large gantry crane will be assembled over the intersection of 4th and Flower to remove the machine’s cutter-head and shield one segment at a time over the next few weekends. After a year’s worth of tunneling with the TBM, crews have safely and efficiently advanced on the goal of connecting all corners of L.A. County.

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