With a railway strike possible in the coming days, Mr. Biden turned to Congress to intervene. He stressed his reluctance to override the will of union workers seeking basic workplace rights, but said it was necessary to address the threat of economic calamity that could be caused by a disruption to the nation’s rail system and an inability to swiftly transport goods and services across the country.
At a news conference at the White House on Thursday, Mr. Biden bristled at a question about why he had not insisted on more paid leave for rail workers in the deal, saying that he had “negotiated a contract no one else can negotiate.” He said he would continue to fight for paid leave for all Americans.
On Capitol Hill, Democrats also said they would have preferred to avoid stepping into the middle of a railroad labor dispute, something Congress has done 18 times in the past century. They groused about being called upon to embrace a deal that went against what workers were demanding. Pressing to overcome those concerns, Mr. Biden dispatched Martin J. Walsh, the labor secretary, and Pete Buttigieg, the transportation secretary, to the Capitol on Thursday to meet with Democratic senators during a private lunch ahead of the votes.
“The consequences of inaction would be severe,” said Senator Chuck Schumer, Democrat of New York and the majority leader. He ticked through a list of what he described as the “serious problems that would occur if there’s a rail shutdown.”
Republicans, too, griped about the position they had been placed in, questioning why Mr. Biden had not allowed for a few more days to resolve the dispute before involving Congress.
To quell the concerns in both parties and speed the measure through the Senate, leaders agreed to first consider the G.O.P. proposal for a cooling-off period and the House-passed proposal to add the paid leave.
“Less than 36 hours ago, we were asked to decide on issues that are complicated, that are important, without necessary deliberations,” said Senator Dan Sullivan, Republican of Alaska, who sponsored the deadline extension. He said his measure would “give negotiators more time to get to an agreement and it will not make Congress the entity of last resort in these kind of negotiations.”