Mayoral candidate Ann Kobayashi's decision to abandon her previous support for rail transit to get the endorsement of former rival Panos Prevedouros is a gamble that the costly transit line between West O'ahu and Honolulu is losing favor among voters and will decide her race against Mayor Mufi Hannemann.

It seems a long shot, with media polls before the primary election showing that nearly two-thirds of O'ahu voters support the 20-mile elevated commute train from East Kapolei to Ala Moana championed by Hannemann.

But some of the same polls showed Hannemann with approval ratings as high as 80 percent, yet he couldn't get 50 percent of the primary vote against Kobayashi and Prevedouros to win outright without having to face a general election runoff.

This gives hope to Kobayashi and rail opponents that the poll results showing overwhelming support for rail were also suspect — especially given the rapidly sinking local and national economies that raise questions about whether we can still afford the most expensive public works project in Hawai'i's history at a cost of some $5 billion in today's dollars.

The councilwoman probably didn't need to change her position on rail to win most of the 28,782 votes Prevedouros got in the primary, but her new anti-rail stance gets her the enthusiastic support of groups fighting to stop the trains via a separate City Charter amendment on whether to authorize rail.

Hannemann has hit Kobayashi hard with accusations of flip-flopping on a number of issues, and now he'll add transit to the list.

As a member of the City Council, Kobayashi was initially a committed supporter of rail, voting with the majority to enact a half-cent increase in the O'ahu excise tax to pay for the trains.

But as she started quarreling with Hannemann on a wide range of spending issues, she formally parted ways with the mayor on rail over the issue of technology; he wanted steel wheels on steel tracks and she backed rubber wheels on pavement.

Kobayashi held to that position during the primary campaign, saying she still supported a transit system, but could do it better and cheaper with rubber-wheeled vehicles.

Now that she's abandoned rail altogether, she'll try to counter the flip-flopping charges by arguing that the sour economy changed everything — that what we could have afforded three years ago or even three months ago, we can't afford today.

Kobayashi, working with Prevedouros, has promised to detail her own plan for traffic relief with cheaper alternatives fitted to the changing economy, and her credibility will depend on how well those proposals resonate with voters.

The city is waffling on whether it will get out its overdue draft environmental impact statement on the transit system before the election — with enough time for voters to digest the information before they vote — and Kobayashi will likely try to exploit this.

In addition to spelling out how the rail line will look, sound and otherwise impact O'ahu's environment, the draft EIS will also contain updated estimates on the cost of building, operating and maintaining the trains.

In this economy, voters might be nervous about giving their approval to the system, and the mayor who advocates it, without full cost information on the table.

It's a steep uphill battle for Kobayashi; Hannemann came very close to the 50 percent vote he needed in the primary and she got only 30 percent.

But she's banking on the unpredictability of this election year and betting all of her chips that rail — and concerns about Hannemann's take-no-prisoners style in pushing it — will rule the outcome.

David Shapiro, a veteran Hawai'i journalist, can be reached by e-mail at dave@volcanicash.net. His columns are archived at www.volcanicash.net. Read his daily blog at blogs.honoluluadvertiser.com.