Attendance and sick leave policies have led to widespread anger and frustration among rank-and-file railroad workers on major freight lines

One of the largest railroad unions narrowly voted to reject a contract deal brokered by the White House, bringing the country once again closer to a rail strike that could paralyze much of the economy ahead of the holidays, union officials announced on Monday.

The union SMART Transportation Division voted the deal down by 50.9 percent, the union said. The Brotherhood of Locomotive Engineers and Trainmen, which represents engineers, announced 53.5 percent of members voted to ratify the deal. The two are considered among the most politically powerful of the 12 rail unions in contract discussions.

The move highlights months of tension between unions and companies across a variety of sectors, as companies have been dealing with labor shortages and workers have taken advantage of more leverage in the workplace to press for better working conditions, more sick pay and more flexible schedules in the aftermath of the pandemic.

The rejection of the contract adds new pressure to the White House, which had been closely involved in negotiating the contract between the unions and rail companies. A shutdown of the nation’s transportation infrastructure heading into the holiday season would spell a political disaster.

Already seven of 12 unions have voted to approve their contracts. But in recent weeks, three of the smaller unions have also rejected their contracts and are back in negotiations.

The main sticking points for rank-and-file members have been points-based attendance policies that penalize workers for taking time off when they are sick or for personal time, and contribute to grueling, unpredictable schedules that weigh on workers’ mental and physical health, they say. In June, a 51-year-old union engineer put off a doctor’s visit, and died of a heart attack on a train weeks later, his family said.

the Brotherhood of Maintenance of Way Employees and the Brotherhood of Railroad Signalmen, have rejected their contracts and would be allowed to strike or companies would be able to impose a lockout even sooner, right after midnight Dec. 5, unless Congress intervenes.

If those unions strike on Dec. 5, all of the unions would likely move in solidarity, provoking an industry-wide work stoppage.

In late September, with less than 48-hours to spare before a railroad shut down, Biden and other top administration officials helped negotiate a last-minute agreement. Points-based attendance policies had been at the heart of that dramatic showdown.

The deal struck included a 24 percent pay increase by 2024 — the largest for railroad workers in more than four decades — and, for the first time, flexibility for workers to take time off when they are hospitalized or to attend three routine doctor’s appointments a year without penalty. The deal also included a single additional paid day off. Currently conductors and engineers do not receive a single paid sick day, but carriers have said their attendance policy allows workers “to take time off when needed.”

But discontent among rail workers continued to brew. They say these concessions did not meaningfully change the points-based attendance policies that carriers began rolling out in 2020 to maintain staffing levels that they said they needed to keep trains running during the pandemic. Union members say the changes have come at the expense of their health.