That may seem bleak, but the Citizens Budget Commission argues the estimate may not be bleak enough.

At issue is the Transformation Plan that the MTA board voted to enact last month. The plan—pushed for by Gov. Andrew Cuomo, who controls the MTA—calls for streamlining agencies and cutting 2,700 jobs in the name of costs savings.

The MTA's budget plan counts on the transformation efforts to save the authority $230 million in 2020 and $538 million in 2023. Those estimates are, as the watchdog report puts it, "highly optimistic."

Both MTA Chairman Patrick Foye and representatives from the firm AlixPartners that wrote the plan, described the proposal as a "blueprint" following its adoption. Despite the lack of concrete commitments, the MTA projects savings at the high-range of even what AlixPartners forecasted its recommendations could produce.

"The Transformation Plan has notable organizational design themes but is light on details," the Citizens Budget Commission's Nora Nussbaum said in the report.

The Citizens Budget Commission added that the plan's implementation could be stalled by civil service constraints and employee backlash to its centralization efforts. The Transit Workers Union has already spoken out against the plan on the grounds it could cut union jobs.

Beyond its critique of the effects of the plan, the watchdog group also argues the MTA is under-budgeting the pay increases likely for union employees through a new contract. The report further warns the MTA that it shouldn't assume its collections from the Payroll Mobility Tax and other revenue sources will continue to grow at levels seen in recent years, during which the city's economy has expanded. If New York's economic growth continued into 2023, it would mark 57 quarters of unbroken growth, "an unmatched feat in modern national economic history," Nussbaum states.

"Even if everything goes according to plan, the authority will run substantial cash deficits in coming years reaching a cumulative total of more than $700 million in 2023," the report concludes. "Importantly, it is unlikely that all will go according to plan."

The CBC recommends that the MTA focus on further detailing the Transformation Plan and realistically assess its potential savings.

MTA spokesman Tim Minton said in an email that the company's dire financials are "no secret."

"The new MTA will be more efficient, focused on delivering quality service to millions of daily riders, while also recognizing the need to significantly reduce costs," he said. "We are facing these challenges strategically, with pragmatism, in touch with the realities of both our revenue streams and expenditure needs."

Read the full Citizens Budget Commission report here.