Notice to the public regarding a class-action lawsuit against Union Pacific was altered without the approval of the presiding circuit judge before it was printed in Arkansas’ largest newspaper.

“I know you’ll take the bullet, but I want to know who the hell did it,” 8th Judicial District Judge Jim Hudson said to lead attorney Thomas Jones of Kansas City, Mo., who is representing the plaintiffs. “If you want to try to avoid depositions, discovery and hearings on this matter, if we’re going to do that, then I need to know who tinkered with my order.”

Hudson certified the ...