Investors holding $1.8 billion of bonds to finance Brightline West, a high-speed rail line between Southern California and Las Vegas, are asserting more control of the project after giving the railroad three more months to inject capital.

Bondholders agreed to extend a deadline for the Fortress Investment Group-backed company to contribute equity to Aug. 1, according to a securities filing dated Friday. The railroad missed an end of March deadline to raise $400 million in capital to continue construction.