Staff has been trained, signals have been tested, but there’s still no opening date set for the Second Avenue subway.

With nearly all work completed on the line’s first phase, MTA Chairman Tom Prendergast said at a Monday committee meeting that he’s “cautiously optimistic” that the agency will open the Second Avenue subway before the year’s end. 

And he wouldn’t elaborate further. 

“That’s as clear as I can state it,” Prendergast said. 

The last of the work needed to open the $4.5 billion project is on track to be completed by Dec. 24, 2016, according to a report from an independent engineer presented to the MTA board on Monday. 

Contractors still need to complete a series of systems testing at all three new stations along Second Avenue — that’s at 72nd, 86th and 96th streets — as well as at the updated station at 63rd street, where the Q train will be routed to head uptown along the new line. 

The tests focus mostly on elevator operation, ventilation and public address systems. 

Kent Haggas, the independent engineer monitoring the project, said as recently as November that an “unprecedented” level of work would be needed for the subway line to open this year. He had for months warned about schedule delays in committee meetings in recent months. 

But on Monday, Haggas said his concerns were abated, thanks to an intensified construction schedule.

“The rate of test completions, which have been a concern of mine for months, have increased greatly and I feel it’s now on track to be finished before the end of the year,” he said, referring to the remaining work. 

Haggas’s report comes after Governor Andrew Cuomo said over the weekend that he “would bet” on the subway line opening in December. Cuomo had visited both the 72nd Street and 86th Street stations on Friday and Sunday, respectively.

Crews have been working around the clock under the pressure of a governor who wants the project, nearly a century in the making, to be delivered by the current set target date. 

“People thought we should probably move the deadline,” said Cuomo on Sunday, during a radio appearance on “The Cats Roundtable” with John Catsimatidis. He mentioned that he would be “dragging” his daughter to the site to prove to her the line could open on time.

“And I said, ‘No, we’re going to stick to the deadline,” he continued, “and we’re going to work like hell to make it,’ and that’s exactly what we’re doing.”

When the stations do open, the Q train will continue north up Second Avenue and serve approximately 200,000 daily riders. The MTA has said that the service would help reduce overcrowding, and related delays, along the nearby Lexington Avenue line.

Veronica Vanterpool, an MTA board member and executive director at the Tri-State Transportation Campaign, asked during the committee meeting if the MTA had a “contingency plan” in case the remaining tests aren’t completed as planned. She asked if the agency would consider opening the new line without all stations ready.

Prendergast declined to elaborate and said that the agency was still looking to open the line within the next 19 days. 

“I think a lot of us have just the same question,” Vanterpool said. “It was an ambitious project. We’ve all been seeing for quite some time it being delayed. So I think we’re all weary about it.” 

Vanterpool said at this point that she’s taking the word of the agency and Haggas. 

“Many of us keep asking, ‘Are you sure?,’” she said. “And Haggas seems confident.

In fear of repeating the issues of 7 line extension in Hudson Yards, MTA Board Member Andrew Albert had been cautioning the agency against opening Second Avenue before it was ready. In the past he had reasoned that a delayed opening would be worth it if it means the subway was up and running efficiently and safely. But Albert too was convinced on Monday that the entire line could open smoothly within the next few weeks.

“And it’s going to really change how people commute around New York,” he said.