The $2 billion Purple Line, a 16-mile light rail project in the Maryland suburbs close to Washington, D.C., was given the green light in June by Maryland's Republican Governor Larry Hogan on condition that funds can be raised. It would connect New Carrollton in Prince George's County with Bethesda in Montgomery County. But as plans are submitted this week, Purple Line supporters should wait to break out the champagne. Required funds have not yet been raised, and the project faces an ongoing lawsuit over potential violations of federal environmental law.

The Maryland Transit Administration proposes obtaining $900 million in grants from the U.S. Department of Transportation and an additional $732 million in federal loans. The state share would be another $1 billion, trimmed from an earlier $1.5 billion. So far, however, no federal funds have been approved, and Montgomery and Prince George's counties have not come up with the required $50 million increase in each of their contributions to the Purple Line's capital costs.

Maryland taxpayers will be left holding the bag if hidden costs balloon or if too few riders show up to generate a profit. They will be guaranteeing repayment of the loans that bidders may secure.

Plus, the Purple Line's $2 billion projected price tag, as well as $58 million a year for maintenance, likely understates the actual cost. As can be seen from costly repairs and slowdowns to the Metro system, maintenance is essential. If the Washington area can't keep its Metro running, why is Maryland — which shares costs for Metro — embarking on another joint rail project?

In addition to the lack of funds, a lawsuit, Friends of the Capital Crescent Trail et al. v. Federal Transit Administration et al., is moving forward in federal court. U.S. District Court Judge Richard Leon approved the schedule for the case in August 2015. A trial will be held next year, with a ruling planned for spring.

The case includes a number of claims under the National Environmental Policy Act, such as failure to properly assess and disclose adverse environmental effects of the projects and reasonable alternatives. Claims under the Endangered Species Act include harm from polluted runoff to federally-protected freshwater species of amphipods in and close to Rock Creek Park.

A report by Friends of the Capital Crescent Trail states that the Purple Line plans fail to contain the water onsite. Opponents charge that the Maryland Transit Authority has not made sufficient provision for the disposal of storm water runoff that will be generated by the rail line and the clearcutting of 48 acres of forest to make way for the project, including on the section of the Capital Crescent Trail that runs from Bethesda to Rock Creek Park and Silver Spring.

No plans are available for containment of hazardous material, including PCBs that could be released from hundreds of sites along the route and combined with the storm water runoff.

Straining credulity, bureaucrats are proposing simply to let excess storm water run into the backyards of the homes along the Capital Crescent Trail, and make its way into adjoining streams through storm drains.

The runoff would set back Maryland's efforts to clean up its downstream waters, making it harder for the state to comply with the Clean Water Act.

In all, the Maryland Transit Authority estimates the Purple Line to attract some 11,800 new riders. With the $2 billion cost, that adds up to over $169,000 per new passenger. For the cost of the Purple Line, each additional rider could have three new Mercedes-Benz E-Class sedans, at $52,000 each, or 8,400 Uber rides at $20 each — enough to get from New Carrollton to Bethesda.

The Purple Line's objectives could be better accomplished using dedicated bus lanes along existing roads, or by widening roads. Let's hope that Maryland comes to its senses.

Diana Furchtgott-Roth is a senior fellow and director of Economics21 at the Manhattan Institute.Thinking of submitting an op-ed to the Washington Examiner? Be sure to read our guidelines on submissions.