The tunnel boring machine (TBM) for the Regional Connector project recently began its journey beneath downtown Los Angeles. The 400-foot-long TBM, known as ‘Angeli,’ will dig the twin tunnels that will connect the Expo, Gold, and Blue Lines.

The new 1.9-mile rail tunnels will be constructed using a combination of tunnel boring machine and an “open-cut” method. Angeli is responsible for 1.1 miles of tunneling between Little Tokyo and the Financial District. Already, the TBM has excavated 1,100 feet and successfully constructed 226 tunnel rings. The TBM can travel upwards of 50 feet each day and excavate 1,300 tons of soil.

Once Angeli reaches the intersection of Flower and 4th streets, the cutter head and its tail shield will be extracted and transported back to Little Tokyo, where tunneling work will begin on the second tunnel. The first tunnel is expected to be excavated by early summer, followed by the completion of the second tunnel in early 2018.

Read more about Angeli and tunnel mining on the project webpage and follow her on Twitter for weekly progress updates and the frequent musings of a two-million pound machine.

The $1.751-billion project is expected to be complete in 2021. When finished, the Connector will create two separate light rail lines — one that runs between Santa Monica and East Los Angeles and the other that runs between Azusa and Long Beach. The two lines will share five stations in downtown L.A. The new arrangement will allow for more frequent and faster light rail service and will either eliminate or reduce transfers for most riders going to and through downtown Los Angeles. The project is funded largely by the Measure R sales tax and a federal grant and loan from the Federal Transit Administration.