Maryland’s transit chief has been replaced just as the state is trying to save its light-rail Purple Line project from a federal lawsuit and is preparing to launch a revamped bus system in Baltimore.

Maryland Transportation Secretary Pete K. Rahn didn’t say why the state had replaced Paul W. Comfort as head of the Maryland Transit Administration. A brief news release Tuesday said only that Rahn had named Kevin B. Quinn, who is designing the new Baltimore bus system, as acting administrator. Quinn previously was the agency’s director of planning and programming.

Erin Henson, a spokeswoman for Rahn, said Comfort left the agency as of Tuesday and is “transitioning out of state government.” She would not elaborate on why he left or whether it was voluntary.

“It’s a personnel matter,” Henson said.

Reached Tuesday evening, Comfort declined to comment on why he left or whether it was his idea. He said only that he’d focused the past two years on the Baltimore bus system redesign and that the timing of his departure “is very interesting.” He declined to elaborate.

“It was a pleasure to serve Gov. [Larry] Hogan and the MTA, and I enjoyed my time there,” Comfort said. “It appears I’m on to the next thing. I’ve got numerous options. … I wish everyone the best.”

Comfort has served as Maryland transit administrator since April 2015. In the Washington suburbs, the MTA oversees planning for the proposed 16-mile Purple Line, which has been stalled in a federal lawsuit since August. Rahn announced last week that the state was scaling back pre-construction work on the line while an appeal in the case is pending. In Baltimore, the MTA is 11 days from launching Baltimore Link, a new bus system announced after Hogan canceled a $3 billion light-rail Red Line planned for the city.

Asked about the effect of Comfort’s departure on both major projects, Henson said Purple Line planning has been led by Rahn and Charles Lattuca, the agency’s head of transit development and delivery. She said the Baltimore bus launch remains on schedule for June 18, noting that Quinn has spearheaded that project.