Honolulu’s rail agency continues to struggle to retain its top-level leaders — those who oversee the largest and arguably most complex public works project in the state’s history.

On Tuesday, Andrew Robbins, executive director of the Honolulu Authority for Rapid Transportation, confirmed that Abbey Mayer, the agency’s latest director of planning, permitting and right-of-way, is leaving the project after 16 months at that post.

“It is with regret that I have accepted (Mayer’s) resignation,” Robbins wrote in an emailed statement. Robbins said that Mayer informed him that he’s leaving for personal reasons.

As HART’s right-of-way director, Mayer led the agency’s efforts to acquire properties along the rail line. He’s the latest in a string of more than 16 managers, directors or top personnel to leave HART, which has struggled since 2015 to retain institutional knowledge as it works to build the 20-mile rail line.

Mayer’s predecessor, Jesse Souki, had the job for just over a year before leaving in November 2016 to become executive director of the Hawaii Community Development Association.

Mayer didn’t respond to requests for comment Tuesday.

He departs as rail construction nears Honolulu’s urban core and the city scrambles to acquire all the properties it will need for the line to run through Kalihi, downtown and Kakaako.

The city has faced particularly tough challenges acquiring properties owned by Howard Hughes Corp. and Victoria Ward Ltd. in Kakaako, with the parties reportedly about $200 million apart in negotiations as of last December.

Another Kakaako landowner facing rail condemnation, Servco Pacific, vented earlier this year that high turnover at HART and its consultants caused negotiations to restart five times “from square one” going back to 2014.

A January 2017 peer-review by the American Public Transit Association also flagged turnover as a worrisome issue at the local agency.

“The frequency of staff turnover is high and impacts project delivery,” APTA’s reviewers wrote. It laid much of the blame on the one-year personal services contracts used to employ much of the HART staff — including Mayer.

Those one-year contracts don’t provide staff with much long-term guarantee of employment, the report found.

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