The city’s troubled rail project took center stage Thursday in an often fiery exchange between Honolulu’s leading mayoral candidates, who appeared together to field questions in their first forum before the August primary election.

Mayor Kirk Caldwell and challengers Peter Carlisle and Charles Djou squared off at the Neal S. Blaisdell Center for a debate sponsored by the Hawaii Lodging and Tourism Association (which is headed by former Mayor Mufi Hannemann). The forum was open to association members only but streamed live on HLTA’s website.

Former Mayor Carlisle and former U.S. Rep. Djou said Caldwell needs to be held responsible for the rail project’s escalating costs, while the incumbent demanded that his challengers offer specifics on what they’d do differently.

Carlisle criticized Caldwell, his successor at Honolulu Hale, for saying that the 20-mile line from East Kapolei to Ala Moana Center should stop initially at Middle Street in light of the financial woes. Carlisle maintains that the escalating costs and delays are largely the result of lawsuits that held up construction.

“We had the plan to continue the rail to where its finishing point should and would be,” Carlisle said, adding that frustration over the project’s progress persuaded him to leave his lucrative law practice and seek a return to Honolulu Hale. “This shouldn’t be half a rail, where we put people on the road back behind where all the traffic already is. That’s a recipe for disaster.”

Carlisle said the project should be completed over the next few years. “We have got to see rail finished, we’ve got to see it put through to the end and we need to do that without delay or putting it off forever,” he said.

Reminding the audience that the price tag for rail was $5.26 billion when Caldwell took office and is now estimated at $8 billion or more, Djou said he bumped into a man on the street who told him that if had lost $100 of his boss’s money, he’d be fired. The city has lost billions of taxpayers’ dollars with rail, and “no one’s gotten fired,” Djou said.

“Responsibility for this disaster that’s going on right now with the rail system has to rest with the chief executive of the City and County of Honolulu,” Djou said. “I believe that the time has come when we have a mayor who’s going to clearly and definitively say, ‘No more tax increases for this rail system.’ Seven billion dollars has got to be enough for a $5 billion rail system. All this chatter and discussion about taking spending to $8 billion or even $11 billion must stop.”

Caldwell said he has never shied away from completing the rail line despite criticisms against him. “I’ve never, ever, ever run from rail. I run to rail, I fought for rail, I campaigned for rail and I am committed to building the entire system, 20 miles, 21 stations, all the way to Ala Moana shopping center,” he said.

Change orders, incomplete designs, bid premiums, overly optimistic cost estimates and lack of control over costs by the Honolulu Authority for Rapid Transportation all contributed to the price escalations, Caldwell said. He has appointed three members to the board who have promised to scrutinize more carefully HART’s operations, he said.

MIDWAY THROUGH the forum, it was Caldwell who went on the offensive, pressing Djou for specifics. “I’ve heard him now repeatedly talk about rail but not talk about a solution,” Caldwell said. “I’ve heard him say he’s stopping at Middle Street. He mentions (Bus Rapid Transit); I want to know about his BRT proposal, real solutions to getting us from Middle Street, if that’s where he’s stopping, to Ala Moana.”

Whatever Djou’s plans are, the mayor said, “it’s going to cost money.”

In response, Djou reminded the audience it was Caldwell and Car­lisle who promised a rail line within a time and cost while he voted against it, and that “build rail better” was a theme of the current mayor’s campaign four years ago. “You have my pledge here that if I’m elected mayor, we are going to end these endless cost overruns, we are going to stop these nonstop delays,” Djou said, again pledging to not raise taxes or spend more than $7 billion.

“I am open to any reasonable alternative that meets those objectives however it occurs,” Djou said, adding, “I am not wedded to any one system, I am not wedded to any one plan. What I am wed to is terminating these enormous cost overruns.” It’s Caldwell, he said, who has failed to come up with a solution, instead asking that the Federal Transit Administration give the city until June to deliver a feasibility plan the agency demanded it get next month.

After the forum, Djou told reporters he would neither ask state lawmakers for an extension of the 0.5 percent excise tax surcharge nor propose raising property tax rates to pay for rail, but would seek private developer help and possibly additional federal dollars to pay for an alternative to ending at Ala Moana Center.

On affordable housing, Caldwell said his administration has pushed a greater number of accessory dwelling units, established Transit Oriented Development areas that give incentives and allowances to those who build affordable units, and is working on requiring developers to provide affordable housing to those on the lower side of the income spectrum.

Carlisle wants the city to butt out of the housing industry. “Whenever the government gets into the housing market, it fails inevitably,” he said. “They screw it up from one end to the other. They don’t kick people out, they don’t keep up with mortgage payments, the place just sits there and deteriorates.” The city began attempting to sell 12 of its housing projects when he was mayor, a plan that would have allowed the units to be renovated. But that plan faltered during Caldwell’s term, he said.

Djou said it’s important for people who were born and raised in Hawaii to be able to purchase homes and continue living here. Meanwhile the island is experiencing a population boom of 10,000 people annually, which requires about 3,000-3,500 units annually. To do that, the city needs to allow higher height limits and offer other incentives to developers who build in the urban core, rather than paving over undeveloped land, he said.

The three will next appear at a forum sponsored by the Rotary Club of Honolulu on July 26.

The primary election is Aug. 13, although absentee mail-out ballots will be sent out beginning July 22. If the top vote-getter captures 50 percent of the votes cast plus one vote, that person would win outright. Otherwise, the top two vote-getters would go head to head in the Nov. 8 general election.

Eight other candidates, none of whom have held elected office, are running for mayor.