Union Pacific is continuing its fight against reinstating a train engineer who defecated on a locomotive connection knuckle.

The company filed an appeal last week to the 8th U.S. Circuit Court of Appeals, the Lincoln Journal Star reported. Last month, a district judge upheld an arbitration board’s decision that the fired engineer should be reinstated because termination was “excessive discipline.”

Union Pacific had sued the employee union to overturn the board’s order to put Matthew Lebsack back on the job. The lawsuit says Lebsack walked past the locomotive cab bathroom on Nov. 20, 2016, as the train was stopped. and  left the locomotive to defecated on the metal knuckle that connects the locomotive to a rail car.

U.S. District Court Judge Brian Buescher of Omaha said in his ruling that he didn’t understand why the board didn’t think Lebsack’s conduct was worthy of upholding his termination.

But Buescher also said the law didn’t let him consider the merits of the arbitration board’s decision, but only whether that decision fell within the board’s discretion under the provisions of railroad-union contract. He said Union Pacific presented no evidence showing the decision was not within its discretion.

– Associated Press