The chairman of the MTA assured state lawmakers Thursday that the agency's $26 billion capital construction plan will have the funding it needs to maintain and expand the downstate region's massive mass-transit network. But that promise comes despite the fact the state has yet to identify the source of some of the funding. Zack Fink filed the following report.

The ambitious five-year capital plan first proposed by the MTA in Sept. 2014 provides funding for the Second Avenue subway and other major system-wide improvements.

But Thursday, the legislators who will be asked to follow through on the state's commitment by allocating some of that money were skeptical during a hearing.

"I consider it really to be an IOU," said state Senator Martin Dilan of Brooklyn. "Basically, the way I understand it, the MTA has exhausted all of its resources."

MTA Chairman Tom Prendergast said he is confident the agency will get the money it needs to move forward.

"I have a very high confidence that the money will be there," Prendergast said. "Not without some challenges of where you find the funding sources. I totally get that. But I have a very high degree of confidence that the money will be found."

Gov. Andrew Cuomo has committed more than $8 billion toward the capital plan.

The agreement came after a dispute with Mayor Bill de Blasio over raising the city's contribution. The mayor ultimately agreed to $2.5 billion.

But so far, the MTA has only gotten $1 billion from the state.

"I have no idea how we can actually do a capital program and actually approve a capital program with language that it'll be there when you need it," said State Senator Martin Golden of Brooklyn. "Corporate America would laugh at this."

In a statement, a spokesperson for the governor said, "The Governor put unambiguous and iron-clad language in the budget to make good on his commitment to provide $8.3 billion towards the MTA's capital plan."

Prendergast was also asked about the planned temporary shutdown of the L train for repairs.

"We are trying to look at the different ways that we can compress that schedule to get it done as short as possible and impact the people, and look at what alternate means of transportation we can provide," he said. "I can give you examples, but we have not landed on any one alternative."

The L train passes through what's known as the Canarsie Tube, which runs underneath the East River and was heavily damaged by Hurricane Sandy in 2012. Prendergast did not provide a timetable for when those repairs would be made, or how long they would take.