CHICAGO (WBBM) – If you hold a Metra monthly pass, and you have been laminating the ticket so that it won’t get torn up — stop.

Metra conductors have been instructed not to accept laminated tickets any more.

The decision stems from apparent ticket counterfeiting incidents on the Union Pacific North Line. Metra spokesperson Meg Thomas Reile said that four tickets have been seized. UP spokesman Mark Davis said one, in Highland Park earlier this month, resulted in an arrest.

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“This one (ticket) didn’t look right, so our railroad police went ahead and investigated,” Davis said.

Each authentic ticket has a number of built-in anti-fraud protections, and Reile said the lamination prevents conductors from checking some of them.

Conditions printed on the monthly passes already barred alteration of the tickets, and Reile said it is Metra’s position that laminating the ticket is an alteration.

Davis said the decision was Metra’s call, and said UP supports it.

“This does curtail theft and fraudulent use of the tickets,” he said.

Reile said Metra does not believe lamination has been widespread. She said most riders who want to protect the paper ticket from the wear and tear of a month’s use do so with plastic envelopes, which Metra supplies. But she said all four of the counterfeit tickets had been laminated.

Metra said anyone holding a September monthly pass who has laminated it can exchange it for a new ticket.