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Purple Line Extension Tunnel Boring Machines (TBM)

Elsie and Soyeon, the twin Tunnel Boring Machines (TBMs) for the Purple Line Extension Section 1 are currently digging two parallel tunnels that will connect three new stations between Koreatown and Beverly Hills.

They started their tunneling journey Fall 2018 at Wilshire/La Brea Station in Miracle Mile and will continue towards Wilshire/Western Station in Koreatown. Once they reach the current Purple Line terminus, they will be dissembled for transporting back to Wilshire/La Brea Station and then reassembled for the last leg of their journey through Wilshire/Fairfax Station and finishing at Wilshire/La Cienega Station in Beverly Hills.

Purple Line Extension Section 1 TBMs, Elsie and Soyeon, inside Wilshire/La Brea Station heading towards Wilshire/Western

The Section 2 TBMs, Harriet and Ruth, will start their tunneling journey from Century City/Constellation Station and head east towards Wilshire/Rodeo Station in Beverly Hills and link up with the Section 1 tunnels at Wilshire/La Cienega Station.

For more information about the TBMs check out the fact sheets .

Follow the @PurpleLineTBMs on Twitter for weekly updates on their progress and more.


The Purple Line Extension Section 1 Tunnel Boring Machines (TBMs), Elsie and Soyeon, are currently digging under Wilshire Bl. They will construct two parallel tunnels to create a seamless connection from the current Purple Line terminus at Wilshire/Western Station in Koreatown to three new stations located at Wilshire/La Brea, Wilshire/Fairfax and Wilshire/La Cienega.

Elsie and Soyeon are responsible for building 17,845 linear feet of tunnels to create approximately 3.9 miles of new subway. They have completed Reach 1 and are on their way to completing Reaches 2 and 3.

Harriet and Ruth, the Purple Line Extension Section 2 TBMs, will be building the connection between the Wilshire/La Cienega and Wilshire/Rodeo Stations in Beverly Hills and the Century City/Constellation Station. They will build approximately 2.6 miles of new subway and will be creating 13,630 linear feet of tunnels. Harriet and Ruth are expected to start tunneling Winter 2019.

Along the way, TBMs will encounter different soil conditions. The tunnel crown will always be at least 20 feet or more under the subsurface water table.

In terms of geology, tunnels will be bored through two types of geological formations: San Pedro and Fernando.

Tunneling Statistics

Progress is measured in total linear feet traveled.

Section 1 Tunneling

Reach

Linear Feet

Location

1

9,570

La Brea Bl to Western Av

2

4,440

La Brea Bl to Fairfax Av

3

3,280

Fairfax Av to La Cienega Bl

4

555

La Cienega Bl to tail track west of La Cienega Bl

Section 2 Tunneling

Reach

Linear Feet

Location

4

6,610

Reeves Dr to La Cienega Bl

5

7,020

Constellation Bl to Reeves Dr


Please use the materials below to learn more about the Purple Line Extension Tunnel Boring Machines (TBMs).

Fact Sheets

Follow the @PurpleLineTBMs on Twitter for weekly updates on their progress and more.