BTS | LA METRO
LA METRO - PAST, PRESENT AND FUTURE
Decades of development of the underground network of Los Angeles metro and plans for the future were described to a packed BTS meeting, in late 2024, in London.
The Chair welcomed the two speakers - Matthew Crow and Amanda Elioff - who had flown in from the US especially to give the talk to BTS. Matthew Crow, Deputy Executive Officer at the Los
Below top: Los Angeles has been developing its metro network in challenging geology.
Below bottom: Layout map of some earlier metro and sewer tunnel projects in LA.
Angeles County Metropolitan Transportation Authority (LA Metro), has worked on development of underground rail transit projects and as Deputy Project Manager for Section 3 of LA Metro’s Purple Line Extension. He started his tunnelling career in the UK with Howard Humphreys, under Martin Knights and Maurice Gooderham. Moving to the US with Brown and Root, he worked on construction management of stormwater and sewer tunnels before working with LA Metro. Amanda Elioff’s background is in planning, design
development and delivery for light and heavy rail subway systems. She has worked on multiple phases of LA Metro.
Her design and construction experience also includes water and wastewater tunnels and an underground physics research facility. She has worked on design and testing of mitigation measures for construction in gassy underground conditions. She is WSP’s Manager for Section 1 of the Purple Line Extension, and Engineering Manager for the San Francisco Bay Area Link21 planning and engineering team, studying a second bay tunnel crossing.
TRANSPORTATION DEMAND Matthew began the presentation, describing the transportation need, the geology and challenges, and the eventual construction of the Red and Gold lines, more recently the Regional Connector, Crenshaw/LAX and the Purple Line Extension. Los Angeles County is a big area, with over 10 million
people, and growing. To the north are the Santa Monica Mountains and the San Fernando Valley. To the south and west are the Westside and the City of Los Angeles. The area has earthquakes, oil fields, gassy tunnelling, and the Los Angeles River. There is hard rock in the mountains. Lower down is the Fernando Formation - a siltstone and claystone, “I guess a bit like a good London Clay”, he said. Above that are sand, silt, gravel, clay, cobbles and boulders. Los Angeles has a significant history of tunnelling over
the last 150 years, including tunnels for railroads, transit, freeways, highways, water and sewers. Historically, the region had a large rail system. Amanda noted that the Red Line, instigated in the 1970s,
was the first heavy rail subway tunnel, extending from downtown out towards the San Fernando Valley. Metro planning has a long history in the area, she adds,
with many starts and stops in funding. Eventually, the state created the LA County Transportation Commission to coordinate municipal operators and create more efficient funding. In 1980, voters approved a tax to help fund transit projects. A locally preferred alternative emerged. However, there was gas underground. Also, there are many oil fields in Southern California.
One particularly famous area along Wilshire Boulevard is the La Brea Tar Pits, where oil seeps out of the ground. In 1985, a non-metro related incident - a methane
explosion - led to the Red Line alignment being re- routed around the tar pit area. A limited methane zone was established. Now the methane zone covers much of the city, and there is also a methane buffer zone. Different requirements apply for construction and investigation in those zones. For instance, the building
10 | June 2026
All images courtesy of LA Metro
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