HONOLULU -- The three leading candidates for Honolulu mayor appeared together for the first time on Thursday in a political forum.

The Kapolei Chamber of Commerce and the West Oahu Economic Development Association sponsored the forum.

The candidates spent a lot of time debating the city's multibillion-dollar rail transit project.

Rail opponent Panos Prevedouros is taking a leave of absence from his job as a University of Hawaii engineering professor to run for mayor.

"Rail is a black hole in city and our taxes for the development. We need real solutions, and rail is not it," Prevedouros said.

Councilwoman Ann Kobayashi said the city has not released enough information to the public to make informed decisions about the rail project.

"The true cost was never given. What is the cost of construction? What is the cost of the operation and maintenance? How will that be funded? Will we be using property tax? We've been asking those questions," Kobayashi said.

Incumbent Mayor Mufi Hannemann, running for a second term, called Honolulu's proposed rail system "one of the best transit projects in America" that should receive up to $900 million in federal funding.

"You don't just say 'Go away.' That is an opportunity to bolster this economy. That is an opportunity to leverage monies for a technology that they endorse: modern rail steel-on-steel. They're not endorsing hot lanes. They're not endorsing rubber on concrete. It's steel-on-steel," Hannemann said.

He said the time for studies is past.

"We want a light rail system. This administration is committed to break ground in 2009 to bring relief to all of Oahu to bolster a sagging economy that's going south fast," Hannemann said.

"We are not getting light rail. We are getting heavy rail. The 0.5 increase in the general excise tax is not sufficient to build it, and it will not solve congestion," Prevedouros said.

City officials said the combined bus and rail system will cost roughly $50 million to $60 million a year to operate. Oahu property taxpayers will subsidize approximately 60 percent of that cost. That is about the same rate as TheBus is subsidized now.

Transit supporters said that is traditional for government to cover the extra costs of transit as a basic service to the public.