OMAHA, Neb. (AP) — BNSF railroad wants a federal judge to prevent two of its unions from going on strike next month over a new attendance policy that would penalize employees for missing work.

The Fort Worth, Texas-based railroad went to court after the unions that represent nearly half of BNSF’s 35,000 workers threatened to strike over the new policy that is set to go into effect on Feb. 1.

Union officials say the policy violates their contracts and could provide an incentive for workers to show up sick.

But the railroad said a strike would hurt the economy too much, and it shouldn’t be allowed because BNSF believes this is a minor contract issue.

BNSF operates in 28 states including North Dakota.