Connecticut’s Democratic senators see two emerging deals totaling some $4.1 trillion as the ticket to modernizing rail in the U.S. Northeast, adding a new wrinkle to the fragile agreements on the legislative underpinnings of President Joe Biden’s economic agenda.

Chris Murphy and Richard Blumenthal are typically reliable votes in an evenly divided Senate where Democrats can spare few, if any, defections on Wednesday’s high-stakes procedural vote to debate a $579 billion bipartisan infrastructure package.

Neither of them have said they would sink that measure, but their last-minute push for more rail financing makes clear that every Democrat has sway in the talks on both the infrastructure plan and a related $3.5 trillion budget blueprint.

“I’m deeply uncomfortable voting for an infrastructure package that doesn’t make significant improvements in the Northeast rail corridor,” Murphy said in a Monday interview, adding that he doesn’t expect to know the outcome of his conversations with negotiators on rail funding by the Wednesday vote.

At a Friday press conference at the Windsor train station in Connecticut, Blumenthal played to the home state crowd.

“Our message to the White House and to our colleagues in the Senate: You ain’t gonna have an infrastructure plan unless you do more and do better for rail,” Blumenthal said.

Back at the Capitol this week, Blumenthal toned it down, saying he “wouldn’t even begin to talk about voting no at this point.” But he made his message—that either or both the infrastructure and spending packages should make rail a priority—clear.

Specifically, Blumenthal and Murphy want to see investments more in line with a 15-year high-speed rail plan that would cut travel times and add new lines throughout the region. As it stands, the proposals before the Senate would pay for just the first few years of that plan, meaning the typical traveler would not see substantial changes, Murphy said.

He suggested that his vote on infrastructure might hinge on assurances he gets that the budget framework addresses his concerns on rail.

“I certainly am going to consider what has been committed to be funded in reconciliation before I decide how to vote this week,” Murphy said.

The infrastructure bill will need 60 votes, and Democrats may be hard-pressed to find 10 Republicans, let alone more than that. The partisan budget blueprint requires only a 50-vote threshold but likely will attract no Republican support.

The infrastructure proposal currently allocates $66 billion to rail over five years, around $30 billion of that would be slated for the Northeast, according to Murphy.

While that package is “generous,” Murphy said, just fixing what’s broken in the Northeast would cost $40 billion. As it stands, the money could finance only the first few projects in the 15-year improvement plan, he added, pointing to proposed improvements at Washington’s Union Station and to bridges and tunnels in Baltimore.

The Northeast Corridor Commission is pushing a $117 billion improvement plan that would aim to cut travel times from New York City to Washington and New York to Boston by 30 minutes, add reverse-peak and off-peak services and generate 1.7 million jobs and $90 billion in earnings over 15 years.

The plan, which Murphy and Blumenthal support, was developed by the federal government, state governments in the Northeast, eight commuter rail agencies and Amtrak.

Murphy also wants to leverage climate initiatives in the budget package as a potential vehicle for increased federal commitment for rail. The commission plan would add 60 million annual trips that emit less carbon than auto or air travel, according to a recent report, as well as new investments in hardened, weather-resilient infrastructure.

Not everyone is convinced.

“I think we have a lot of conversations yet to be had on high speed rail,” said Representative Jim Himes, a Connecticut Democrat.