Democrats on a Maryland Senate panel grilled Gov. Larry Hogan’s nominee for transportation secretary Monday about the future of the Purple Line light-rail project and decided to call him back for more questions before voting on his confirmation.

It did not appear that the nomination of Pete K. Rahn was in serious jeopardy, but his rocky confirmation hearing — which also touched on several other controversies — highlighted continuing tensions between the Democratic-led legislature and the new Republican governor.

Besides putting off a vote on Rahn, the Senate Executive Nominations Committee delayed decisions on four other Hogan nominees Monday night, with one Democrat accusing Hogan’s choice for environment secretary of “dodging and weaving” in his responses to the panel.

After the hearings, Senate President Thomas V. Mike Miller Jr. (D-Calvert) predicted that some of Hogan’s nominations would draw some no votes from Democrats when they reach the Senate floor. “But I think they’ll be confirmed,” Miller said, adding that the Senate should give Hogan wide discretion in choosing leading members of his administration.

Before Monday, the Senate had voted on 12 other of Hogan’s Cabinet nominees, approving all of them, though some after delays. Hogan spokesman Doug Mayer said the governor is confident that his latest batch of nominees will ultimately be successfully as well.

“Governor Hogan has selected some of the best and brightest from Maryland and around the country to serve the people of our state,” Mayer said. “We have the utmost confidence that these talented and dedicated individuals will be confirmed.”

Several Democrats pressed Rahn about the likelihood that Hogan will move forward with the Purple Line, the planned 16-mile rail connection between Prince George’s and Montgomery counties. Hogan expressed skepticism about the project during last year’s campaign, saying Maryland needed to focus more on building roads.

Transportation officials said last week that they were pushing back by five months a major bid deadline for companies seeking to build and operate the $2.45 billion project.

Rahn said Monday that he has asked the firms to find ways to cut the project’s cost without altering the line’s length or route. He said he is maintaining “an open mind” on both the Purple Line and a light-rail line planned in Baltimore. “I have not precluded these projects going forward,” he told the senators.

Rahn was also pressed on Hogan’s proposal to cancel scheduled increases in gasoline taxes, which Democrats contend would leave very little money for either mass transit or road projects in coming years.

Rahn said that the department he has been nominated to lead is “not a tax policy department” and that his job is to operate it with the money he has.

Sen. Jamie B. Raskin (D-Montgomery) also started to press Rahn on a controversial highway project that he oversaw while leading the New Mexico Transportation Department in the late 1990s. The project was awarded to a sole bidder, a subsidiary of Koch Industries, whose owners, Charles and David Koch, are major donors to Republican candidates and conservative causes nationally.

Ben Grumbles, Hogan’s nominee to lead the Department of the Environment, faced tough questioning Monday about his views on the use of hydraulic fracturing, or fracking, to harvest natural gas.

Maryland is likely to decide in the next few years whether to open parts of Western Maryland to the drilling practice, which environmentalists say threatens drinking water and poses other risks. Grumbles said that “science needs to be a driving force” on the decision.

Miller said he found Grumbles’s answers straightforward. But after Grumbles left, Sen. James Brochin (D-Baltimore County) said he thought the nominee was “dodging and weaving” and suggested that he be called back for more questioning as well.

Raskin said a decision on Brochin’s suggestion would be made sometime before the panel meets again next week.