Monday, August 8, was supposed to have been a day of celebration for Maryland’s  Purple Line, as state transportation officials and the Federal Transit Administration would officially ink an agreement for a $900 million New Starts grant for the new $5.6 billion light rail system across Washington, D.C.’s northern suburbs.

But because a federal judge has set aside the FTA’s record of decision for the project, the ceremonial pens will stay on the shelf until…well, nobody is really sure when.

The Purple Line seemed poised to begin its $2 billion construction phase this fall as one of the nation’s first major public-private partnerships for transit. This past June, the Maryland Department of Transportation and the Maryland Transit Administration reached financial close with Purple Line Transit Partners, LLC, on a 36-year agreement to design, build, operate, finance and maintain the 16-mile, 21-station light rail system from Bethesda to New Carrollton.

On August 3, however, a federal judge agreed with project opponents, who claimed that long-term ridership calculations in the Purple Line’s Environmental Assessment did not fully consider what has been a sharp decline in rider volume on the trouble-plagued Metrorail system. MTA had already been criticized for a lack of transparency in how its ridership projections were formulated.

Although Metro is operated by a separate agency, the Washington Metropolitan Area Transit Authority, and uses different transit technology, transfers to and from the rail system are projected to account for 27 percent of the Purple Line’s ridership by 2040, according to MTA estimates.

Metrorail is in the midst of a year-long, multi-million dollar accelerated maintenance program that both WMATA and MTA claim will help restore the system’s safety and reliability, and bring passengers back in time for the Purple Line’s scheduled 2022 start-up date.

During testimony in the case earlier this summer, the agency claimed that recalculating the Purple Line’s ridership numbers might delay the project by six months. Because the judge’s order makes the Purple Line ineligible for any federal funding, Maryland is urging FTA to take the case to federal appeals court as quickly as possible.

In addition to the New Starts Grant, the Purple Line had also been OK’d for an $875 million TIFIA loan, and $313 million in Private Activity Bonds issued by the Maryland Economic Development Corporation. Purple Line Transit Partners—made up of Meridian Infrastructure Purple Line, LLC; Fluor Enterprises Inc.; and Star America Purple Line, LLC—was also set to contribute $138 million to get the project underway. There has been no comment from the private partners as to their continued commitment to the project.

This is not the first crisis for the Purple Line, which has been under discussion for more than 15 years. Environmental and community groups, including those who brought the lawsuit, have long criticized light rail’s potential effect on neighborhood’s and a popular recreational trail, advocating instead for a bus rapid transit option. It was only after $600 million in design, construction and operations cuts, plus increased local contributions in 2015 that Gov. Larry Hogan (R) deemed the project’s financial risk to the state palatable, approving the Purple Line while canceling a $2.9 billion light rail project in Baltimore.