Acting rail Executive Director Mike Formby says he intends to leave that post — and his work at the city — in early November.

By that time, Honolulu rail officials have signaled, they hope to have found an interim director for the Honolulu Authority for Rapid Transportation who can help further move the severely cash-strapped transit project beyond the era of former Executive Director Dan Grabauskas, who resigned in August, and into an uncertain future.

In an email Thursday, Formby said he has “no current plan” to return to his post as the city’s Department of Transportation Services director.

“My personal philosophy in life has always been to move forward and not back,” said Formby, who left DTS on Aug. 18 for what was believed to be a temporary period to lead HART. “There are so many new and interesting things I’ve yet to tackle in life.”

Formby’s announced departure came a day after Mayor Kirk Caldwell’s office told the Honolulu Star-Advertiser that the city’s legal counsel has determined Deputy DTS Director Mark Garrity, who’s filling in as the department’s acting director, can also fill Formby’s seat on the rail board of directors.

Last month, city officials said Garrity would not fill Formby’s HART board seat because Garrity is only the acting DTS director.

Along with Garrity, the city’s acting Department of Planning and Permitting director, Art Challacombe, will fill a seat normally occupied by his boss, George Atta, on the HART board. Atta recently went on medical leave.

Having the city’s two acting directors on the HART board will help keep the oversight group’s ranks from shrinking as the transit project’s fiscal crisis grows. The mayor’s office announced Garrity and Challacombe would fill the board seats two days after the Star-Advertiser asked if Caldwell had concerns about mounting vacancies on the HART board and whether the matter might hinder the group’s ability to oversee rail during such a critical time.

Caldwell spokesman Jesse Broder Van Dyke said the city’s legal counsel determined sometime last week that Garrity could serve as a HART board member.

As acting DTS director, Garrity “has all of the powers and duties of the agency head, including occupying the HART board,” Caldwell’s office stated in an email, as part of the legal justification for the move.

Some HART board members interviewed this week about looming vacancies before the city shared its decision about the acting directors did not appear to know that Garrity and Challacombe would be joining their ranks. HART board Chairwoman Colleen Hanabusa said she learned Tuesday after speaking with the Star-Advertiser.

Caldwell often touts his appointment of Hanabusa to the volunteer, unpaid rail board as a solid pick to help get a better handle on the massively overbudget project — but she’s now running to reclaim her former congressional seat. Hanabusa says she’ll step down from HART sometime before the Nov. 8 election.

Caldwell, who faces a fierce re-election fight against former Congressman and City Councilman Charles Djou, is “in active discussions regarding candidates” to replace Hanabusa, his office’s email stated Wednesday. “It will be difficult to fill her shoes and we wish she could stay, but the necessary search has commenced.”

Additionally, state Department of Transportation Director Ford Fuchigama has been able to attend only two meetings since May 2015, according to online HART board minutes and officials with the semiautonomous government agency. Fuchigama sits on the board per Honolulu city Charter. In January, he informed his rail board colleagues that he wouldn’t be able to attend most of this year’s meetings due to his state responsibilities.

With Garrity and Challacombe able to fill seats, the HART board avoids being as lean as it has ever been in its more than five years directly reviewing and setting policy for rail.

The island’s elevated transit project, which also happens to be the state’s largest public works project ever, currently faces an uncertain future with daunting cost overruns of at least $1.5 billion.

The city’s two acting directors are slated to attend their first board meeting Thursday at Kapolei Hale, according to a rail spokesman. The DPP director is the only one on the 10-member board who doesn’t vote, but his attendance helps the HART board keep its quorum.

Honolulu’s city Charter requires that those two director positions also serve as ex-officio members on the HART board.

Formby had served as Caldwell’s DTS director since January 2013 before taking the helm at HART in August.

Meanwhile, HART board member Terrence Lee said Wednesday he is confident “based on what I’ve seen and heard so far” that the HART board could have an interim executive director running the agency prior to Nov. 8. The City Council appointed Lee to the rail board in 2015.

“HART needs to move on. This is too important a position,” Lee said, referring to the executive director job. The agency needs to focus on recovery and financial plans for rail that will satisfy its federal transit partners in the months ahead, he said.

“There is a very definite sense of urgency,” Lee added.