The Los Angeles County Metropolitan Transportation Authority (Metro) has announced the start of work on the third and final portion of the Purple (D Line) Extension Project.

The $3.6bn Section III project will connect downtown Los Angeles with the Westside via a high-speed subway by 2027.

The US Department of Transportation has provided a federal grant of almost $1.3bn for the project.

To mark the beginning of the construction work, a ground-breaking ceremony was held by Metro on Monday (24 May).

The ceremony was attended by the Federal Transit Administration (FTA), the US Department of Veteran Affairs and the University of California, Los Angeles (UCLA), as well as federal officials.

Los Angeles City Mayor and Metro board chair Eric Garcetti said: “The Purple Line Expansion is the key that will unlock our transportation future and open doors of opportunity across our city, and [Monday’s] ground-breaking moves us one step closer to completely redefining our relationship with public transit.

“We promised Angelenos a world-class transit system when we passed Measure M, and this milestone is a clear indication of our commitment to make Los Angeles a more accessible, sustainable, and inclusive city.”

Under the project, two previous subway legs will be linked through Koreatown, Beverly Hills and Century City and extended towards Westwood by 4km.

A station will be built at the West Los Angeles Veterans Affairs Medical Centre to provide services for the hospital campus, while another will be built at Westwood Village and UCLA.

Metro is currently involved in the construction of all three sections of the subway extension.

The first section, which runs between the Wilshire/Western station and Beverly Hills, is almost 70% complete and expected to open in 2024.

Section II is almost 45% complete and due to be opened in 2025, while Section III is 20% complete and will open in 2027.

FTA deputy administrator Nuria Fernandez said: “The FTA is proud to partner with Metro and the entire Los Angeles region to bring more transportation options to residents, veterans, students and visitors to the 2028 Summer Olympics through the Purple Line extension.

“This project is an excellent example of a transformational infrastructure investment that the Biden-Harris administration supports. It will improve access and mobility for millions of people travelling in one of Los Angeles County’s most congested corridors.”