The city’s troubled rail project is pivoting to an uncertain “Plan B” to complete the final 4.16-mile push to Ala Moana while looking at the possibility of new leadership Thursday.

Andrew Robbins, CEO and president of the Honolulu Authority for Rapid Transportation, told the Honolulu Star-Advertiser on Tuesday, “My contract expires at the end of the month. The indication is that my contract will be expiring. So I’m going to enjoy my last several days here with this terrific staff.”

The HART board’s Human Resources Committee is scheduled to meet in executive session Thursday to discuss what’s described on its agenda as “HART Leadership Transition.”

Robbins, the city’s highest-paid employee, is HART’s sixth leader in nine years. The potential for an interim appointment Thursday to replace Robbins after his three-year contract expires in two weeks would represent the seventh top leadership change since voters approved the HART concept in 2010.

Meanwhile the cost estimates keep rising to build the 20-mile, 21-station route from Kapolei to Ala Moana.

“I would expect it to come in around $10 billion at this point in terms of the forecast, perhaps a little under,” Robbins said. The completion date is now expected sometime in 2028.

Robbins had been pushing for a so-called public-private partnership — or P3 — agreement to finish the final leg of construction. Then in August the city announced that it was pulling its support for the P3 idea.

On Tuesday, HART and the city separately unveiled the cost proposals from two hui of bidders: City Center Connection Group and Imua Transit Honolulu.

Both came in with construction estimates that were more than $2.7 billion, or 60% more than HART’s $1.7 billion “affordability limit.”

But Robbins believed there was at least one more round of “last and final offer” discussions to be held before giving up on P3.

“We view this as preliminary,” he said while reviewing the proposals in HART’s offices. “We could reasonably expect 4% or 5% reduction.”

“The city didn’t want to do that, and they wanted us to withdraw, and I took a lot of heat for not canceling right away,” Robbins said. “That is the reality of what it’s going to take to build City Center.”

HART is mandated to build the entire 20-mile rail project all the way to Ala Moana — the state’s largest transportation hub, providing public transportation connections into Waikiki and on to the University of Hawaii.

The final leg includes building the proposed Pearl Highlands transit center, eight stations and a 1,600- stall parking garage, which would be critical for commuters from Leeward Oahu, Central Oahu and the North Shore.

But the City Center construction through town is plagued by plenty of risk for contractors.

The push through Iwilei is particularly difficult because of the need to relocate overhead Hawaiian Electric Co. power lines underground and deal with other utility lines below busy and congested Dillingham Boulevard.

HART still does not have ownership — or even easements — to what Robbins called “little slivers of land” to move utility lines and clear the way for contractors to begin construction.

“We’re just out of space,” Robbins said.

He estimates that it will take at least another year to acquire all of the property or easements to deal with utility lines.

The uncertainty makes it hard for potential contractors to nail down their construction schedules, Robbins said.

“They can’t really start building until the utilities are cleared out of the way,” he said. “Dillingham Boulevard is sort of the trunk line of the city that services Waikiki and downtown. You’ve got water, sewer, gas, then you’ve got three different, high-level voltage levels from HECO mostly above ground that we have to underground.”

Mayor Kirk Caldwell on Tuesday said the two P3 proposals to build rail’s City Center leg through a P3 approach were out of reach.

“To get that price down would be almost impossible,” he said.

Because the bids were 2% apart and in “the same range,” Caldwell said, “you’re getting a true reflection of the construction costs. … So we know the costs are much higher than what HART anticipated.”

Caldwell proposed that HART instead award contracts on a more traditional “phased awarding of bids. It’s going to be a slower approach, but I think it’s a more transparent approach and it’s a more responsible approach to just build to the degree that you have the money to build the next phase. But we can still build over this period of time and get to Ala Moana. It may take a little longer, but we’ll do it in a way that we can afford it.”

Robbins said HART already has reached out to contractors to get their initial “design -build” bids to finish rail’s final leg, and expects their initial responses in late January, which would then be presented to the City Council and the HART board.

“Now we have to make Plan B work as best as possible,” he said.

Asked what he wished he had known before taking the job, Robbins said, “The political challenges, quite frankly.”

Robbins had been told that HART was created as a semi- autonomous city agency. But he then trailed off before completing his thought.

“HART was designed to remove politics, but in a major project that moves across a major city …”