LITTLE ROCK, Ark. — A federal judge has ordered a mental evaluation for a retired Union Pacific Railroad employee accused in a conspiracy to steal a 95-ton locomotive from a North Little Rock rail yard.

U.S. District Judge J. Leon Holmes this week ordered Gregory Stokes to report to the Metropolitan Detention Center in Los Angeles by July 20 to undergo a mental exam for schizophrenia, the Arkansas Democrat-Gazette reported. Stokes is from Texas but lives in Utah.

"The report must state whether Gregory Richard Stokes is suffering from a mental disease or defect that renders him mentally incompetent to the extent that he is unable to understand the nature and consequences of the proceedings against him or to assist properly in his defense ... and whether he was insane at the time of the offense," Holmes' order read.

Stokes' attorney, Danny Glover, was out of town and not available for comment Friday. However, a defense motion requesting the mental evaluation said Stokes' mental capacity had deteriorated to the point that he could not stand trial.

Stokes, Richard McCown and Tracy Young were indicted in May 2010 on five counts of wire fraud stemming from what authorities said was a scheme to steal a Union Pacific locomotive.

McCown, also a retired Union Pacific employee, pleaded guilty June 17 to one count of wire fraud but hasn't been sentenced. Last month, Holmes approved federal prosecutors' request to dismiss the indictment against Young.

Prosecutors said at McCown's plea hearing that Stokes approached McCown about switching the identification number on the train to one owned by Young and moving the locomotive to Young's rail yard. The men would then split $60,000. Young is the president of Lone Star Locomotive Repair LLC and the Orange Port Terminal Railway in Orange, Texas.

McCown said he had never spoken to Young, according to a court transcript.

"I don't know what he even looks like. That (part of the scheme) was between him and Stokes. ... Young and Stokes, I don't know what they did," the transcript says McCown said.

Young, who also owns the Victoria Generals, a summer collegiate baseball team, declined to comment after the indictment was dismissed.

Stokes is scheduled to go on trial Dec. 5, pending the results of his mental evaluation.

McCown could face up to 20 years in prison and a $250,000 fine when he is sentenced.