Plenary-led Momentum Alliance Partners has signed a co-development agreement with the California High-Speed Rail Authority in California, US, to explore private investment and delivery models for the future expansion of the state's high-speed rail network.

Momentum Alliance Partners comprises global firms with expertise in infrastructure investment, rail operations, engineering, systems integration and commercial development, including Plenary Americas, CDPQ Infra, Keolis, SNCF Voyageurs, Jacobs, Sener, SYSTRA, Setec, Arup and Steer. Under the agreement, the consortium will undertake a six-month predevelopment and delivery assessment to identify strategies for expanding California's high-speed rail network beyond the Merced–Bakersfield section currently under construction. The study will examine project sequencing, delivery approaches, financing options, operational planning and opportunities for private-sector participation in future phases, building on construction progress in the Central Valley, where track and systems installation is scheduled to begin later this year.

Momentum Alliance Partners will also evaluate long-term commercial opportunities along the high-speed rail corridor, including broadband and fiber-optic infrastructure, data facilities, utility and transmission corridors, station-area development, and strategic land-use partnerships. These initiatives are intended to enhance the project's long-term financial sustainability while supporting future network expansion. Leveraging its global expertise in financing, developing, constructing, operating and commercializing large-scale rail and infrastructure projects, the consortium could also contribute to future phases of the project if the California High-Speed Rail Authority pursues additional partnership opportunities.

Construction of the California high-speed rail project is progressing across the state, with 171 miles of the Merced–Bakersfield corridor currently in the design and construction phase. More than 80 miles of guideway have been completed, while 61 major structures are finished and another 30 are under construction across Madera, Fresno, Kings and Tulare counties. Overall, 463 of the planned 494 miles between San Francisco and Los Angeles/Anaheim have received full environmental clearance, positioning those sections for future construction.