Last year, rail officials reached a deal with Hawaiian Electric, Co. for taxpayers to avoid spending an additional $130 million in utility work along the transit line’s western half.

It was a rare financial bright spot for the island’s 20-mile, 21-station public works project, which has repeatedly struggled to stay on budget during the past three years.

But recent changes to the Honolulu Authority for Rapid Transportation board prevented that oversight body Wednesday from finalizing the deal with HECO.

Now, that cost-saving agreement is unexpectedly in limbo — and HECO says its ability to access all the overhead lines running along rail’s western guideway remains compromised.

“We’re already in a situation where for us it’s difficult to do our maintenance,” a visibly frustrated Kathy Yonamine, HECO’s Project Management Division director, told the board Wednesday.

“It took us several years to get to this point,” and it could take the same amount of time to renegotiate the deal if necessary, she said.

For years, HART and HECO have wrangled over what to do about the overhead utility lines that run too close to the rail guideway that’s being built. Consultants flagged the issue in 2009 but there’s no record of any follow-up until 2013.

In February, they reached a deal for the city to buy 15 specialized trucks for HECO that extend vertically like a telescope, allowing the utility to safely access most of the westside lines.

The city would still have to pay to bury some lines underground. That change covering the trucks and westside work totaled about $70 million.

The deal hit a snag Wednesday, however, when the HART board voted 7-1 in favor of it.

Previously, seven votes would have been more than enough for approval. But as part of rail’s most recent, $1.4 billion bailout package, state leaders increased HART’s board membership to 14.

The new state-appointed members don’t vote on agenda items — they’re on the board to give the state better oversight over rail’s progress. Nonetheless, eight of HART’s nine voting members now must vote “yes” for a measure to succeed because that reflects the new 14-member majority.

“We do need eight votes,” HART board member Ember Shinn lamented Wednesday.

Glenn Nohara, the ninth voting member, didn’t attend Wednesday’s meeting. Then, board member John Henry Felix voted against the change order because he didn’t think the city negotiated a good deal with HECO. So the deal was not approved.

During its nearly seven-year history, the HART board has mostly voted unanimously and it rarely fails to approve change orders, which typically add project costs. On Wednesday, it was unable to approve a change order that’s estimated to save taxpayers about $130 million.

Board Chairman Damien Kim called the deal a “no-brainer.”  If the city doesn’t buy those trucks, it would likely have to bury all the westside lines underground instead — and officials estimate that would cost about $200 million.

Meanwhile, HECO is using standard trucks to do some work along the westside, but there are power line sections there that it can’t service “and that’s a concern,” HECO spokesman Jim Kelly said in an email Thursday.

As construction of the guideway moves further east, the utility could be unable to service other lines without the new trucks, he added.  As long as there’s no deal in place, the overhead utility access will be a problem.

On Wednesday, Yonamine told the board that the situation is “not optimal.”

After the vote, the HART board immediately went into executive session, where its members presumably discussed what to do.  When they emerged, they reopened discussions on the HECO deal and decided to defer it to their meeting next month.

Some board members, including city Transportation Services Director Wes Frysztacki, wondered why the city didn’t have a deal with HECO to get reimbursed if the utility uses the specialized trucks on other utility lines away from the guideway.

“Again, if not for the project, we would not need to get” the special trucks, Yonamine testified.

Mayor Kirk Caldwell and the HART board hope that Honolulu voters might fix their new quorum and voting challenges by approving a city charter amendment later this year.