A California-based entrepreneur has approached the city with a solution to keep the popular Koko Crater tramway open to hikers — a zip line cable ride that would send riders flying 3,000 feet down the side of the crater at speeds of up to 55 mph.

Steve Klein, owner of Alt-E Ventures, said his $750,000 proposal is "fully funded" and could generate enough revenue for safety improvements and maintenance of the abandoned World War II-era tramway.

The city closed the entrance to the hike in February, citing danger from the nearby Koko Head Shooting Complex, then reopened it that same afternoon after residents protested.

Since then, maintenance has emerged as a key issue for the city. The future of the tramway is still under discussion. The route is not a designated trail and no one group has been maintaining the abandoned wooden ties, although hundreds of people use them for exercise and recreation each week.

"I thought, well, maybe this would solve everything," Klein said by phone from San Diego on Wednesday.

"What I'm proposing is, let's make this a great park with a new attraction and take part of the funds and use them to maintain the trail."

Klein has not yet made a formal proposal to the city, but he detailed his plan in an e-mail sent to city Parks Director Lester Chang on Tuesday.

A copy of the e-mail was made available to The Advertiser by Klein.

Chang said yesterday that he had referred the proposal to the 13-person committee formed by the city to consider ways to keep the tramway open.

"It's pretty early for me to comment on it," Chang said. "We're always looking for new ideas and new possibilities, so it does seem intriguing from that standpoint."

He acknowledged that any commercial business within Koko Head District Park would change the nature of the area.

"It would be a whole new ball game," he said.

Committee members contacted about this story said they had not seen the proposal and declined to comment. The group's next meeting is Thursday.

NO O'AHU ZIP LINES YET

Several zip line tours are operated on Kaua'i and one on Maui, but none yet on O'ahu. It would take about eight months to put the attraction in place, including the permitting process, if the city is open to the proposal, Klein said.

From a platform at the 1,208-foot summit, riders would be strapped into sitting harnesses and slide down the outside of the crater along 3,000 feet of cable at a 34 percent grade, parallel to the tramway. The ride would brake automatically as riders reach a second platform at the base of the crater.

As the proposal stands, people would hike to the summit, then ride down only. Each ride would cost about $20, Klein said. About 100 riders are expected each day, with 25 rides per hour, according to the plan.

Alt-E Ventures' partner company, ZipRider, has built similar rides in California, New Hampshire, Alaska, Siberia and four locations in Utah, including the Utah Olympic Park.

The cable and two platforms can be blended into the surrounding environment with little impact, Klein said.

Proposals for similar attractions have not been warmly received by the community in the past. In 1999, a city plan to install a cable-car system to the summit of the crater was shot down by residents.

Hawai'i Kai Neighborhood Board chairman Greg Knudsen, who looked over Klein's proposal this week, said he expected the zip line idea would meet a similar fate.

"It looks like an exciting attraction, but it is not appropriate for Koko Crater," he said.

Knudsen was also concerned that the attraction would open the door to a restaurant or gift shop at the Koko Crater summit and other commercial businesses at the base of the crater.

HIKERS WARY OF IDEA

Many hikers on the tramway yesterday were hesitant about the proposal.

"That sucks. That's not a workout," said Kahala resident Michael Bertolacini, who had just returned from the hike.

Bertolacini said most people who frequent the park are looking for exercise — not an amusement ride.

"I think, financially, it would be a pit," he said. "I don't think anyone would go up there. ... It's not green, it's not lush, it's not Hawai'i."

Also hiking yesterday was Royce Bowman of Kalihi, who said he would accept the zip line "if it helps keep the trail open."

"I love this trail so much," he said. "It's such a big part of my fitness routine."

"I don't think it's a great idea," said Shawna Cooper, who goes up the track about two times a week. "I'd like to see it kept the way it is."

"I think it would take away from the natural beauty," said 'Aiea resident Bill Oshiro, who was hiking with Cooper yesterday. But, he added, "I would take my daughters.

"I guess it would be kind of cool, in a way. If you got all the way to the top and didn't want to hike down, you could catch a ride down."