The House of Representatives on Wednesday voted to approve a bill to block a potentially crippling US rail strike – but also to mandate paid sick time for the workers.

In the US Senate, Bernie Sanders, the Vermont independent who caucuses with Democrats, announced that he would object to fast-tracking Joe Biden’s proposal that Congress impose an industrial settlement, until he can get a roll-call vote on the amendment that would guarantee seven paid sick days for rail workers.

The House voted 290-137 to impose a tentative contract deal that had been reached in September, but which four key unions had refused to join, on a dozen unions representing 115,000 workers.

The US president, who built a reputation on being pro-labor and put himself at loggerheads with the unions after asking Congress to avert a strike, had warned of the catastrophic impact of a rail stoppage that could begin as early as 9 December and could cost the US economy about $2bn a day by some estimates, with chaos hitting freight and passenger traffic.

On Tuesday, the House speaker, Nancy Pelosi, and Senate majority leader, Chuck Schumer, indicated they would attempt to push through a bill to impose the settlement, albeit expressing reluctance.

Workers expressed dismay at the stance of Biden and his administration.

On Wednesday, the House passed the bill to block the strike and, separately, voted 221-207 to give seven days of paid sick leave to railroad employees, a plan that faces an uncertain fate in the evenly split Senate. Democrats and some Republicans have expressed outrage over the lack of paid short-term sick leave for railroad workers.

“We know much more needs to be done for railroad workers,” Pelosi said ahead of the votes. “No one should be at risk of losing his or her job by staying home when sick, needing to see a doctor or getting lifesaving surgery.”

A rail strike could freeze almost 30% of US cargo shipments by weight, stoke already surging inflation, cause widespread job losses and strand millions of long-distance Amtrak passengers and commuter rail services.

After the vote, Biden called on the Senate to act “urgently”.

“Without the certainty of a final vote to avoid a shutdown this week, railroads will begin to halt the movement of critical materials like chemicals to clean our drinking water as soon as this weekend,” he said in a statement.

Asked if Biden supported the separate House measure to require sick leave, the White House press secretary, Karine Jean-Pierre, said that the president broadly supported paid sick leave for all Americans “but he does not support any bill or amendment that would delay getting this bill to his desk”.

Railroad companies and the US Chamber of Commerce oppose amending the contract deal that was struck in September largely on the recommendations of an emergency board appointed by Biden.

The influential business lobby group said the sick leave, if passed and signed into law, “would impose an unworkable, one-sided modification to a labor agreement”.

Biden on Monday praised the proposed contract that includes a 24% compounded pay increase over five years and five annual $1,000 lump-sum payments, and had asked Congress to impose the agreement without any modifications.

There are no paid short-term sick days under the tentative deal, after unions asked for 15 and railroads settled on one personal day.

“This all could have been avoided had the railroads been willing to provide their employees with a basic protection and what so many Americans already have: paid sick time,” the House transportation committee chair, Peter DeFazio, said.

Ian Jefferies, chief executive of the Association of American Railroads, said House action on sick leave could undermine future collective bargaining and argued the unions had historically bargained for higher overall wages and a more generous long-term leave policy.

The contracts cover workers at carriers including Union Pacific, Berkshire Hathaway’s BNSF, CSX, Norfolk Southern Corp and Kansas City Southern.

The transportation secretary, Pete Buttigieg, and labor secretary, Marty Walsh, are expected to speak to Senate Democrats on Thursday about the rail labor issue.