BNSF railroad’s two biggest unions that represent 17,000 workers won’t be able to go on strike over a new attendance policy they say would penalize employees for missing work for any reason.

A federal judge ruled last Tuesday that a strike would likely violate federal law because under their contracts railroad unions aren’t allowed to strike over minor disputes. Instead, those must be settled through arbitration or negotiation.

Judge Mark Pittman said a strike would hurt BNSF and could cause significant damage to the economy because of the role the railroad plays in delivering all kinds of goods.

“The record further establishes that a strike would exacerbate our current supply-chain crisis — harming the public at large, not just BNSF,” Pittman wrote.

The Fort Worth, Texas-based railroad went to court earlier this month after the Brotherhood of Locomotive Engineers and Trainmen, and the Transportation Division of the International Association of Sheet Metal, Air, Rail, and Transportation unions said they were considering going on strike to protest the new policy that went into effect today.

The unions said they were surveying their members about whether they would support a strike because the stringent new rules would sanction workers for taking sick time or time off to attend a family member’s funeral. They said the rules would provide an incentive for workers to come in when they are sick even if they have COVID-19 symptoms and punish local union officials who take time off to represent workers at disciplinary hearings.

Union officials didn’t immediately respond about the ruling.

Under the new policy, engineers and conductors begin with 30 points, and then points are deducted from that for absences, with the deductions ranging from two points to 25 points. A worker can earn four points back by being available to work for 14 days in a row including weekends. An employee would be disciplined when their points are exhausted.

BNSF said it came up with the new system to modernize its policy and give its employees an easier way to see where they stand under the rules, and make sure it has enough employees available to staff its trains. The railroad said it believes its new attendance rules will still allow employees to take time off for vacations and deal with obligations outside of work.

The railroad said in a statement that it will work with its employees to help them adjust to the changes that BNSF executives believe are needed.

“We understand that change can be an adjustment, but working together with our employees, we believe we can adapt to meet today’s competitive freight environment,” the railroad said in a statement.

BNSF is one of the nation’s largest railroads, and it operates 32,500 miles of track in 28 western states.