HANDOUT PHOTO: Henry Kay announced Aug. 26 that he is leaving his job as the Maryland Transit Administration’s executive director for transit development and delivery to pursue a private sector job. Kay has been one of the state’s top planners on the Purple Line. (Courtesy of Maryland Transit Administration)

This post has been updated.

Henry Kay, one of the Maryland Transit Administration’s top planners on the light-rail Purple Line project, is leaving his state job.

As the MTA’s executive director for transit development and delivery, Kay has been integral to planning for the 16-mile east-west Purple Line proposed to link Prince George’s and Montgomery counties. His last day is Friday.

In an interview Thursday, Kay said his leaving the agency is “totally voluntary” because he wants to pursue a private sector job. Though he has worked primarily for Democratic governors, Kay said his departure isn’t related to Republican Larry Hogan recently taking over the governor’s mansion. After months of hand-wringing over the fate of Maryland’s transit projects following Hogan’s election in November, the governor recently killed a 14-mile light-rail Red Line planned for Baltimore, a project that Kay also oversaw. Hogan approved a cheaper version of the Purple Line — now estimated to cost about $2 billion — but reduced the state’s contribution by more than $500 million.

Kay said he’d been considering leaving government work for awhile but stayed on at the MTA to ensure a smooth transition after Hogan’s election. He said he doesn’t know where he’s going next because state employees aren’t allowed to negotiate for jobs in industries that they do business with.

“I finally decided to make the leap,” Kay, 50, said. “I’m excited about it.”

Kay also has been a key point of contact for Montgomery and Prince George’s officials pushing for a Purple Line.

“In good times and in bad, he continually advanced the public imperative of providing a transit connection in the inner Beltway suburbs of Washington, D.C.,” said Montgomery County Council President George Leventhal (D-At Large).  “He’s certainly been a pivotal policy maker” on the project.

Kay joined the MTA in 1998 as the agency’s director of planning until 2004, working mostly under former governor Parris N. Glendening (D). Under then-Gov. Robert Ehrlich’s (R) administration, he spent several years overseeing transit initiatives for the Baltimore business community’s Greater Baltimore Committee. He returned to the MTA in 2007 under then-Gov. Martin O’Malley (D).

Bids on a 35-year contract for a team of private companies to design, build, operate and help finance a Purple Line’s construction are due in November. State officials have said they hope to have the winning team begin final design and construction by mid-May.

[Previous editions of this story incorrectly said Ronald Barnes, MTA’s senior deputy administrator and chief operation officer, had been chosen to replace Kay. MTA officials say Barnes is a candidate for the job, but no replacement has been chosen.]