The cost of the city’s rail project is now expected to swell to $6.57 billion as rail officials Thursday made public a new outline of the rail financial plan that incorporates additional utility work, traffic signals and finance charges that had not been included in previous cost estimates.

Honolulu Authority for Rapid Transportation officials also announced the projected opening date for the entire length of the 20-mile project will likely slip again, with the latest projections showing the entire project is now expected to open to the public in the last quarter of 2021.

The official rail financial plan the city submitted to the Federal Transit Administration in 2012 projected that the rail project would cost $5.26 billion and that the entire 20-mile driverless train system would open by mid-2020.

The new projections are part of a financial and scheduling update for rail that is required by the FTA, and mark the third time in a year that rail project planners have publicly amended their calculations to account for delays or project cost increases.

The financial plan outline made public Thursday incorporates $1.524 billion that HART expects to receive from the five-year extension of the half-percent general excise tax surcharge to fund rail. That surcharge extension was approved by the state Legislature and Gov. David Ige this year but still needs the approval of the Honolulu City Council.

The Council’s Budget Committee is scheduled to take up Bill 23, giving authorization for the surcharge, at its meeting at 9 a.m. Wednesday in the Council committee room.

The committee announced Thursday it will hold additional public hearings on the bill Nov. 5 at Kapolei Hale and Nov. 9 in the Washington Middle School cafeteria. Both of those meetings are scheduled for 5:30 p.m.

The Council would then take up the measure — if it passes out of committee — for the second of three required full Council votes.

Daniel Grabauskas, chief executive officer of HART, said that if the excise tax surcharge is extended, “the amount of money that is necessary to cover all of the projected cost increases plus contingency are all covered.”

“That’s really the message that we want to send to folks, is that no one’s going to come back to be asking for more money than the extension that was already passed by the Legislature and the governor,” he said.

Former U.S. Rep. Colleen Hanabusa, who recently joined the HART board of directors, said, “The general public just doesn’t understand how the budget can go off that much, and why they weren’t apprised of it along the way.

“I think people are going to be unhappy,” she said of the latest project cost projections. She said some people recall earlier, lower cost projections, and wonder what happened to cause the price of rail to escalate. However, the board itself won’t know the actual costs of the project until all of the bids are in and the contracts are signed, she said.

“But you know what? The public doesn’t want to hear that,” Hanabusa said. “They want to know, ‘What is it going to cost us when this project is done?’ And quite candidly, we can’t tell them that because we don’t even know what it is.”

The draft outline of the new rail financial plan includes $220 million in new construction and financing costs for the project, including an additional $95 million in borrowing costs the project will incur. The revenue from the extended tax surcharge will not actually begin flowing into HART’s coffers until after 2022, and the authority will have to borrow more money than previously projected to cover its construction costs until that extra tax revenue arrives.

The new expenses announced Thursday also include an additional $70 million for replacement and relocation of power, sewer and other utility lines along the rail route, with much of that money to be used to place utilities underground in a 2-mile corridor along Dillingham Boulevard.

Other planned add-ons announced Thursday include $20 million for additional escalators in rail stations in the city center portion of the project, and $20 million for additional traffic signals and other intersection improvements along the rail route.

The preliminary new financial plan also sets aside $299 million in additional “contingency” funding that would remain in reserve and be available to cover additional unexpected costs.

“We’re just trying to be more prudent, more conservative with those numbers. They are still cost estimates,” Grabauskas said. “What we’re trying to do is track against escalating costs in the construction market. Everybody knows there is a boom in construction, and we’re just trying to make sure that we’ve set aside enough money now that when the time comes that we open those bids, we can cover the costs.”

Longtime rail opponent Cliff Slater said he believes there will be more cost overruns to come as the city begins work on the crowded city center leg of the project, and predicted the project will eventually cost $8 billion or $9 billion.

As for the public response to the new estimates, Slater predicted people will be upset, “but will they be upset enough to threaten the re-election of the Council members?” he asked. “Not being into politics, I can’t guess at that, but it would take real anger on the part of the taxpayers to make a difference in the actions of the City Council.”

So far the city has built four miles, or 20 percent, of the elevated guideway, and is about 80 percent finished with construction of the rail operations center near Leeward Community College, according to HART officials.

The city has also acquired about 73 percent of the land it needs to built the rail line from East Kapolei to Ala Moana Center, and delivery of the first rail cars is expected in the first quarter of 2016.