Clear communication, conducted openly, is vital to completing the city’s rail project as efficiently as possible. Yet even with facts as knowable as the dimensions of the guideway and locations of power lines, that communication hasn’t happened as it should.

And now there is a huge disconnect between the plans by the Honolulu Authority for Rapid Transportation and the safety protocols of the Hawaiian Electric Co. crews working on them.

That’s a disconnect that must be bridged, lest it produce more harrowing cost increases for the project already topping the $6 billion mark.

The problems actually began some seven years ago — before HART was created — in discussions involving city officials and the consultants hired to do the early planning work. A review of the documents presented in the Sunday Honolulu Star-Advertiser by writer Marcel Honore traced the history of the information exchange.

It’s been wholly unacceptable, another example of don’t-rock-the-boat concealment and avoidance of the hard facts. Unfortunately, that kind of bureaucratic tap-dance is all too commonly seen in Hawaii governance.

What were those hard facts? At the core, they were that HECO advocated for greater clearance from power lines than are stipulated in federal safety regulations.

On one end there was an apparent decision by the consultants to tamp down concerns. One, according to the HART records, was Hank Wei, who worked with the firm Parsons Brinckerhoff on the project.

“Please do not share this email with HECO,” Wei wrote in 2009, and then added that he thought 20-foot clearances between power lines and the rail guideway’s edge would work. He was addressing his remarks to rail engineers after the utility informed them its crews should have clearances of 50 feet for working on high-voltage power lines.

As appalling as such a statement is, it would appear from the public record that HECO also sidestepped the specifics for too long. The utility cites a 2008 document as an early communication with the city consultants that “additional clearances would be required for operations and maintenance of overhead power lines.”

But in that document, HECO did not specify what those additional clearances were. That would have been a good time for all concerned to get these important specifications nailed down.

Brennon Morioka, HART’s deputy executive director, this week expressed hope that the agency can come to terms with HECO in a way that would limit the additional costs.

The alignment along Dillingham Boulevard has for some time been recognized as too narrow to provide adequate clearance for the 138-kilovolt high-power lines running adjacent to the route, Morioka said. HART already has budgeted the money needed to underground the lines there, he added.

Westward of Middle Street, Morioka believes equipment capable of maneuvering in smaller spaces — narrower bucket trucks, for example — can provide a less costly solution. Even at $200,000 a pop, a fleet of these trucks would be cheaper to purchase than undergrounding all of the 138-kv lines, he said.

The taxpayer has to hope he’s right — and that HART will be able to work through another disagreement.

In addition to the amount of clearance, in recent weeks HECO has underscored its preference that undergrounding of lines be completed before the Dillingham segment is constructed. That could delay the project even further.

HECO spokespersons insist that there have been repeated and specific communications to HART — “multiple emails” — on all of this. The taxpayers should see these emails. And the HART board owes it to them to demand that HART management and the utility put everything in the public record.

The rail project construction is advancing, ever so slowly toward town, where the conflicts with existing infrastructure and communities will intensify, even under the best of circumstances.

Instead, the halting, vague and scant communications about core issues offer up the worst of circumstances. There needs to be an all-hands-on-deck moment to straighten this out, minimizing the pain for the taxpayers.

Both HART and HECO, which is proposing its own transformation through a merger, need the indulgence of the public to get through the coming months and years. They’ll never get it — without a turnaround in performance.