In the latest Hawaii Poll, a clear majority — 57 percent — of poll respondents said that Honolulu’s massive and increasingly costly rail transit project should proceed. In 2011, the number was only 49 percent.

It’s a curious result.

Since 2011, the rail project has been plagued with construction delays, massive cost overruns and frustrating traffic disruptions. One would have expected support for rail to decline, not increase.

But perhaps a sense of inevitability has taken over. Recently the City Charter Commission, while considering several proposed Charter amendments related to rail, set aside the three that would have stopped or shortened the rail route.

“I’m OK because it got started, right?” said Kapolei resident and poll respondent Bert Lee. “Once it got started, it’s too expensive to knock down and stop a project.”

The City Council faces that sense of inevitability on Wednesday, when it is expected to give final consideration to Bill 23 (2015), which would extend the 0.5 percent surcharge on the general excise tax by five years, to 2027, to complete construction of the rail transit system to Ala Moana Center.

The Council needs to pass the extension to keep rail on track. But it also needs to avoid potential complications that could delay and raise the already high cost of the project.

An earlier version of the bill, proposed by Council Chairman Ernie Martin, would have capped the extended tax at $910 million and directed any surplus toward addressing the city’s homeless and affordable housing needs.

Martin’s proposal needlessly complicated matters, as the tax is authorized only for rail-related purposes and $910 million was not expected to cover the full cost. So earlier this month, the Council’s Budget Committee approved an amended version of the bill for the full Council to consider. It would raise the extended-tax cap to $1.1 billion and change the uses for any surplus.

The bill specifies that any money collected over the cap “may be expended for” certain defined uses: contingency and reserves recommended by the Federal Transit Administration; improvements to aid accessibility for those with disabilities; planning and design of route extensions; and “infrastructure improvements to rail station areas to support affordable housing.”

Yes, these purposes are rail-related. But the cap remains a bad idea. What if the defined uses prove to be not needed? Can the Honolulu Authority for Rapid Transportation apply the money to other, more pressing needs? Will the Federal Transit Administration object to the cap?

A spending cap on a multi-billion project that needs to be built, and for which six miles of guideway have already been installed, could add uncertainty and the possibility of more expensive delays.

Of course, it’s possible the revised language of the cap is enough to avoid such a result. But why take the risk?

Even so, Martin and the Council cannot be faulted for their concern about HART’s spending.

With the original project estimate of $3.7 billion ballooning to $6.57 billion — overwhelming a $1 billion “contingency” fund meant to cover cost overruns — Martin and the Council are reflecting the concerns of worried and dissatisfied constituents, who surely want more than vague explanations.

The bill rightfully requires a more detailed accounting of the work and the billing of both the general contractors and, significantly, the subcontractors.

It is hoped that the increased transparency will provide the public with a better accounting of what it’s paying for — a much-needed alternative mode of travel through Oahu’s major population centers.