The Purple Line will begin carrying passengers in the Maryland suburbs later than expected because of a court fight over the project, but state officials believe it can still open in 2022, state Transportation Secretary Pete K. Rahn said Thursday night.

The line had been scheduled to open to riders in March 2022. Rahn said the state and its contractor are still redoing the construction schedule, but he believes it can open “sometime” later that year.

“We know there are going to be some delays,” Rahn told the audience at a Silver Spring forum sponsored by the Purple Line Now advocacy group.

He said state officials should have a better sense of the timing — and any additional costs to the project’s $2.4 billion construction costs — in a couple of months. He said he expects that project officials can make up some of the time lost during the one-year legal fight over the line’s environmental impacts. A second lawsuit filed against the project is still pending in federal court, but judges have allowed construction to continue.

Construction on the 16-mile line between Montgomery and Prince George’s counties began in August, after a federal appeals court restored the project’s environmental approval.

Early construction work has focused on cutting trees, particularly along the Georgetown Branch recreational trail between downtown Silver Spring and downtown Bethesda, and beginning to move utility lines. He said 75 percent of the design work is complete, and the state has acquired 88 percent of the right of way needed along the alignment.

The state’s contractor, a team of companies called Purple Line Transit Partners, has about 375 people working on the project and will ramp up to about 1,500 people this year, he said.

Rahn told the crowd the state has spent $200 million of the $325 million in federal aid that Congress has appropriated to the Purple Line. The state expects the rest of the total $900 million in federal grants to be doled out in annual appropriations of about $100 million to $125 million, he said.

“We are spending money quickly,” Rahn said.

The state still expects the line to attract about 59,000 trips per day when it opens, he said. That number is expected to grow to 74,000 daily trips by 2040.

“If the service is as good as we think it’s going to be,” he said, “I’m very confident in those numbers.”