Her Work Done on Crenshaw’s Underground Railroad, Harriet the Tunnel Boring Machine Retires

Harriet the Tunnel Boring Machine ready to retire. All photos by Joe Linton/Streetsblog L.A.
Harriet the Tunnel Boring Machine ready to retire. All photos by Joe Linton/Streetsblog L.A.
Map of Metro Crenshaw/LAX light rail line. Image via Metro fact sheet
Map of Metro Crenshaw/LAX light rail line. Image via Metro fact sheet

Earlier today, Streetsblog L.A. got the chance to go deep below Crenshaw Boulevard to attend Metro’s retirement ceremony for the tunnel boring machine (TBM) that has completed its work on Metro’s Crenshaw/LAX line. The machine is named “Harriet” after the heroic abolitionist Harriet Tubman.

The new Crenshaw/LAX line started construction in early 2014. The project is currently over 60 percent complete. The 8.5-mile line will extend through South L.A. and Inglewood from the Expo Line’s Crenshaw/Exposition Station to the Green Line’s Aviation Station. The new light rail includes portions above, below, and at grade.

For a good overview of the Crenshaw/LAX project, watch a fly-through video embedded in this earlier SBLA article.

Despite some construction delays, including some due to heavy rains this winter, the Crenshaw/LAX line is expected to open to the public in Fall 2019.

Harriet dug two one-mile-long tunnels at the north end of the Crenshaw/LAX line. The tunnels extend below Crenshaw Boulevard from Exposition Boulevard to Vernon Avenue. This stretch of the line will have three underground stations: Crenshaw/Exposition, Martin Luther King Jr. Boulevard, and Leimert Park. South of Vernon Avenue/Leimert Park, the line runs on the surface.

There is no elevator at Metro’s construction site at Leimert Park. Event attendees were lowered down into the construction site via a metal cage lowered and raised by a crane.

Fully-assembled tunnel boring machine. Image via Metro fact sheet
Fully-assembled tunnel boring machine. Image via Metro fact sheet

The Leimert Park Station underground box is cavernous–quite a bit bigger than completed Metro subway stations. At the northern end of the site sat Harriet’s 21.5-foot diameter cutter head, attached to its 30-foot-long cylindrical shield. The fully-assembled tunnel boring machine is 400 feet long, weighs 950 tons, and is operated by a crew of 75 workers in three shifts.

Harriet began tunneling at Expo/Crenshaw on April 26, 2016 and completed its first tunnel on October 20. It was then shipped back to Expo/Crenshaw, and dug its second tunnel from November 29 through April 6. The TBM tunneled at a rate of roughly 60 feet per day.

Metro Crenshaw/LAX Line leadership in front of Harriet: John Fasana, Mark Ridley-Thomas, Jacquelyn Dupont-Walker, Phil Washington, and Peter Shea.
Metro Crenshaw/LAX Line leadership in front of Harriet: John Fasana, Mark Ridley-Thomas, Jacquelyn Dupont-Walker, Phil Washington, and Peter Shea.

The retirement ceremony featured brief remarks by Metro leadership including board Chair John Fasana, County Supervisor Mark Ridley-Thomas, boardmember Jacquelyn Dupont-Walker, CEO Phil Washington, and contractor representative Peter Shea. Washington stressed the importance of this major transportation infrastructure project, improving lives now through creating middle class jobs, and later through improved mobility helping South L.A. access education and jobs.

Below are more photos from today’s event.

A Crenshaw/LAX tunnel dug by Harriet
Looking north from the Leimert Park Station site, a completed Crenshaw/LAX tunnel dug by Harriet
Closer view of tunnel machine cutter head
Closer view of a portion of the 21.5-foot diameter tunnel boring machine (TBM) cutter head
Even closer view of cutter head feature
Even closer view of one cutter head element
The back of the TBM's head
The back of the TBM’s head
Closer view of the back
Closer view of the back of the TBM head
xxx
Scaffolding below Crenshaw Boulevard, with Harriet the TBM is in the distance
The view south of the Leimert Park Station site, as the track bed slopes up to surface level
View south of the Leimert Park Station site, as the track bed slopes upward to where Crenshaw/LAX rail will run at grade in the middle of Crenshaw Boulevard

Congratulations on your underground railroad, Harriet!

For more information on the Metro Crenshaw/LAX line, see Metro’s project page.

  • Justin Runia

    Good video on how a tunnel borer works:

ALSO ON STREETSBLOG

Metro Lowers ‘Angeli’ the Regional Connector Tunnel Boring Machine

|
This morning, Metro celebrated the ceremonial naming and lowering of the Regional Connector subway tunnel boring machine. Metro’s newest TBM – another is currently tunneling portions of Metro’s Crenshaw/LAX light rail line – is named “Angeli.” The winning name was proposed by Windsor McInerny, a student at Woodrow Wilson High School. McInerny was joined by […]

Metro April News: Crenshaw Work Stoppage, All Door Boarding, and More

|
Today was the April meeting of Metro’s board of directors. There was nothing earth-shatteringly controversial on the agenda, but below are a handful of updates. Crenshaw / LAX Construction Work Stoppage As mentioned on SBLA Twitter and explained in this headlined L.A. Times article, safety violations caused Metro to take the unprecedented step of stopping construction on […]