Jeff Zients was the man to make the trains run on time. It’s been a bumpy start.

The grumbling has already begun over Joe Biden’s new chief of staff.

Less than two months into his role as top White House aide, Jeff Zients faces frustration among progressives who see his influence behind Biden’s recent tack toward the center.

House Democrats are still stewing over Biden’s about-face on a D.C. crime bill that blindsided them, and left vulnerable lawmakers to deal with the political fallout. And within a wider circle of White House allies, Zients’ arrival has sparked complaints that they are cut out of the loop after enjoying direct West Wing access through his predecessor, Ron Klain.

“There’s a transition going on in the administration,” said Rep. Pramila Jayapal (D-Wash.), who chairs the Congressional Progressive Caucus. “We were looking forward to developing a good relationship with Jeff Zients, but at this point, we’re not in that place yet. So we're still working on it."

Jayapal later added: “We're getting to know each other.”

Inside and outside the administration, there is concern over whether Zients has the political instincts and Capitol Hill relationships to deftly navigate a crucial period ahead of Biden’s anticipated reelection run, according to interviews with 16 administration officials, lawmakers and others with knowledge of the internal White House dynamics, some of whom were granted anonymity for fear of retribution.

Every chief of staff faces critics and criticism, often from within the building. Klain endured the same. But Zients’ emergence provides an early test of whether someone without decades of Biden world experience can help the president navigate the political waters. It also will help illuminate whether someone without an extensive political background can manage one of Washington's most crucial positions.

Zients has his defenders, who say it’s too early to judge and that the complaints have more to do with getting used to a new management style. They stress he is in constant contact with Democrats on the Hill.

But there are early signs that Zients himself recognizes the learning curve he's up against. Whereas Klain routinely made his own policy and political recommendations to the president, Zients frequently brings in other senior advisers — including Steve Ricchetti and Anita Dunn.

Three administration officials with knowledge of the matter also have said Ricchetti now regularly sits in the daily chief of staff meetings that Biden used to hold one-on-one with Klain, though they stressed Zients gets solo time with the president, too.

White House officials said Zients bringing aides into meetings reflected his way of creating a more “inclusive” environment.

The White House did not make Zients available for comment. But in an email, Klain defended his successor: “What I’m hearing from old White House colleagues and from key allies on Capitol Hill is that Jeff is off to a great start — building on the progress of the past two years, with effective outreach and open communication.”

A longtime corporate executive who previously co-chaired Biden's transition and directed the White House’s Covid response team, Zients was tapped to bring his managerial skills to the broader day-to-day operations. But six weeks in, congressional Democrats say the decision making in the West Wing has grown more opaque — spurring confusion over policy priorities and debate over how much responsibility Zients is and should be carrying.

One adviser in close touch with a range of key House Democrats graded Zients’ first months on the job bluntly: “I would give him a C-,” the person said. “It’s a generous C-.”

There are signs that Zients is taking steps to shore up his standing among Hill allies. White House officials say he has done consistent outreach to the Hill in his first weeks, speaking with more than 50 lawmakers, including Senate Majority Leader Chuck Schumer and progressives including Sens. Elizabeth Warren of Massachusetts and Bernie Sanders of Vermont.

On Wednesday, Jayapal said Zients called and spoke with her for roughly 30 minutes on a number of caucus issues, including the expansion of overtime eligibility for workers. She said he has called before and that Zients also dropped in on her meeting last week with National Economic Council Director Lael Brainard.

Democrats acknowledged that much of the dissatisfaction may be the result of growing pains as White House operations adjust to Zients’ leadership style. While Klain was distinctly hands-on with nearly every issue — taking part in policy debates, staying in close touch with an array of lawmakers and advocacy groups, and occasionally frustrating aides with his demands and the bottlenecking of decisions — Zients has sought to bring more structure to the process.

That means meetings are more formal and decision making follows a more established procedure, compared to the culture that funneled nearly every development through Klain’s office. Zients — a former management consultant — has shortened White House meetings (often described as too lengthy during the Klain era) in an effort to boost efficiency, preferring to check in frequently with individual aides and teams for updates throughout the day.

“The White House is a quick-paced place and from Jeff on down, we are maximizing every minute,” deputy press secretary Andrew Bates said. “So if we have a 15-minute meeting, it's because the meeting only needs to be 15 minutes. And if the meeting needs to be an hour, he'll make it an hour.”

Zients also leans on his deputy, Natalie Quillian, for tasks like tracking the implementation of major legislation that Biden believes will underpin his case for reelection, four people with knowledge of the internal dynamics said.

“Ron was unique in his own talents and abilities around how busy and a whirling dervish of activity he could be,” said Faiz Shakir, an adviser to Sanders who kept in frequent touch with Klain. “[Zients] runs it as you would a CEO at a larger corporation: I have people for that, give them space."

Five officials acknowledged changes and growing pains, but insisted both are a natural part of any major transition.

“When you have the leader leave and another person comes in, of course there's change. Of course there's a change in how people work, and organizations adapt to that,” Dunn, a senior Biden adviser, said in a phone interview Wednesday. “Change is not necessarily a bad thing. And it's not necessarily an improvement from what happened before. It's just different and they [Klein and Zients] are different, and they both have enormous strengths.”

Worries about Zients have been shaped by a series of White House decisions made shortly after the 56-year-old moved into his new role. On Zients’ second day, most House Democrats opposed a bill seeking to repeal a major revision of D.C.'s criminal code after the administration issued a statement that appeared to support the local overhaul.

But weeks later, Biden reversed his position, vowing on March 2 to sign the repeal if it reached his desk. The announcement upset House Democrats who felt they had taken a tough political vote for no reason. More infuriating, lawmakers and aides said, was the way the White House went about it.

Biden made no mention of his newfound support for the bill during a private meeting with House Democrats only the day before, nor had any White House officials offered preemptive warnings. It was only when Biden met with Senate Democrats the next day that he disclosed his plans. At the time, D.C. Del. Eleanor Holmes Norton said she learned about the news when asked by reporters during a Congressional Black Caucus press conference. And other fellow Democrats were left unsatisfied after they tried to press White House aides for more information as they read reports about Biden’s conversation with Senate Democrats.

Asked in the aftermath what members needed to hear from the White House, Rep. Gerry Connolly (D-Va.) said the administration needed to have “some honest conversations with people who feel they walked the plank.”

Senior Biden aides admitted to a communication breakdown, blaming inexperience in the White House in dealing with veto threats. Zients has since ordered changes to the communication process, they said.

That puzzlement has only been compounded in recent weeks by lawmakers’ similar struggle to get answers over reports that Biden may reinstitute family detention at the southern border in a bid to limit migration. The prospect alarmed Latino lawmakers and immigration advocates, and came as the lawmakers have also openly criticized the administration’s proposal to clamp down on asylum eligibility.

Zients’ defenders downplayed the complaints, arguing that the shift from Klain was bound to be jarring for some. On top of that, his arrival coincided with a particularly busy period for the White House that prevented Zients from making the typical get-to-know-you rounds. Some Democrats also acknowledged that Biden's priorities and outreach may need to shift as he positions himself for reelection.

"At the end of the day, as a Democrat, do you want a Democrat in the White House or not?" said Rep. Salud Carbajal (D-Calif.). "So you kind of have to swallow circumstances. We don't like it. I don't like it. But, you know, you just have to understand that reality."

While Biden has taken positions of late that have left traditionally progressive groups in dismay — including the approval of a drilling project in Alaska that enraged environmental groups but thrilled labor unions — Zients has also overseen a relatively productive stretch. The president rolled out his latest budget proposal, turning it into a political cudgel against House Republicans, and he and his team are now in the midst of trying to avert a financial crisis after a pair of regional banks failed.

The sprint to stabilize the banking sector following Silicon Valley Bank's collapse offered a clear example of the management skills that catapulted Zients into the highest ranks of government, allies said.

“It was a race to get things done before the market opened, and he knows this stuff. He’s good at it,” said one Zients supporter who was in touch with him during the effort. “There was nothing that was not decisive and clear.”

More broadly, some in the White House who chafed under Klain’s leadership view Zients as a welcome change, describing an environment that’s become more professional and influenced less by the chief of staff’s own day-to-day priorities.

On the Hill, some Democrats said they’ve felt the positive effects of having new blood at the top of the White House. Rep. Ann Kuster, the chair of the moderate New Democrat Coalition, said Zients called her on his first day as chief of staff and has remained in close touch.

Jayapal said one element of her relationship with Klain she enjoyed was “just to be able to call or text when I need to. And so far that’s been working pretty well” with Zients, too. She called her relationship with the new chief of staff a work in progress, but said she’s eager to see it improve.

“Ron did say to me, ‘Give him a chance, Congresswoman. You didn’t know me either,’” Jayapal said.

Sarah Ferris contributed to this report.