Political leaders in New York have been promising an overhaul of Pennsylvania Station in Manhattan for so long that the saga has started to resemble the Arthurian legend of the sword in the stone.

One by one, officials have tried to pull off ambitious renovation schemes, and one by one they have failed.

On Thursday, President Trump’s transportation secretary, Sean P. Duffy, joined the list. Asserting federal control of the station in a surprise announcement, he vowed to transform it into a safe, clean station that “reflects America’s greatness.”

In all the years of political wrangling, consensus building and master planning, the many obstacles to a new Penn Station have never been challenged so directly by the power of a president. Nor has anyone tried the strong-arm tactics that have defined the first few months of Mr. Trump’s second term.

Now, Mr. Trump’s methods — aggressive demands, bullying, bluster, disregard for legal and bureaucratic structures — will be put to the test against a problem that has for years been mired in a tangle of political cross-pressures and conflicting priorities.

Transportation experts say that under normal circumstances, a thorough renovation of the nation’s busiest transit hub, which serves three different railroads, would most likely take several years and cost several billion dollars. This isn’t China, where a rail station can be upgraded seemingly overnight, they say.