The Senate convened for a rare weekend session on Saturday with the majority leader, Chuck Schumer, encouraging the authors of a bipartisan infrastructure plan to finish writing their bill.

Several senators predicted that the text of the bill would be ready for review but it was not done when the Senate opened late in the morning. Nor was it ready when the chamber recessed after four hours of minimal activity. Rather, work was still taking place behind the scenes and it was unclear when votes would occur.

Schumer said he understood that completing such a large bill is a difficult project, but warned that he was prepared to keep lawmakers in Washington for as long as it took to complete votes on both the bipartisan plan and a budget blueprint that would allow work later on a massive, $3.5tn social, health and environmental bill.

“The longer it takes to finish, the longer we will be here, but we’re going to get the job done,” Schumer said.

The bipartisan plan is also big, with $550bn in new spending over five years beyond typical highway and public works accounts. Adding the anticipated spending in those accounts in the next five years bumps up the total cost to nearly $1tn. A draft bill circulating Capitol Hill indicated it could have more than 2,500 pages.

It is being financed from funding sources that might not pass muster with deficit hawks, including repurposing untapped Covid-19 relief aid and relying on projected future economic growth.

Among the major investments are $110bn for roads and bridges, $39bn for public transit and $66bn for rail. There’s also $55bn for water and wastewater infrastructure and billions for airports, ports, broadband internet and electric vehicle charging.

A bipartisan group of senators helped it clear one more hurdle on Friday and braced to see if support could hold during the next few days of debate and efforts to amend it. Schumer wants the voting to be wrapped up before senators break for their August recess.

“We may need the weekend, we may vote on several amendments, but with the cooperation of our Republican colleagues I believe we can finish the bipartisan infrastructure bill in a matter of days,” Schumer said on Friday.

John Cornyn, a Texas Republican, predicted: “It’s going to be a grind.“

Shortly after the Senate began the procedural vote on Friday, it was stopped. Cornyn said the reason was that some of the text in the draft bill did not comport with the agreement between the negotiators. The rare bipartisan work is testing senators’ ability to trust one another.

Several moments later, the vote resumed and the effort to proceed to consideration of the bill passed by a vote of 66-28.

Earlier this week, 17 Republican senators joined all Democrats in voting to start debate. That support largely held on Friday, with Minority Leader Mitch McConnell again voting yes.

But whether the number of Republicans willing to pass a key part of President Joe Biden’s agenda grows or shrinks will determine if the president’s signature issue can make it across the finish line.

Cornyn said he expects Schumer to allow all senators to have a chance to shape the bill and allow for amendments from members of both parties.

“I’ve been disappointed that Senator Schumer has seen fit to try to force us to vote on a bill that does not exist in its entirety, but I hope we can now pump the brakes a little bit and take the time and care to evaluate the benefits and the cost of this legislation,” Cornyn said.

Rob Portman, an Ohio Republican, and Kyrsten Sinema, a Democrat from Arizona, released a statement on Friday saying they were close to finalizing the legislative text.

The outcome with the bipartisan effort will set the stage for the next debate over Biden’s much more ambitious $3.5tn spending package, a strictly partisan pursuit including childcare, tax breaks and healthcare. Republicans strongly oppose that bill, which would require a simple majority, and may try to stop both.