Update: A correction was made to the headline and second paragraph to clarify Benjamin Sheets' job title as the former head of Amtrak at Union Station in Chicago. The Polar Express Train Ride in Chicago has become synonymous with the holiday season.But the train ride is also the basis of a criminal indictment issued against the former head of Amtrak at Union Station in Chicago.Benjamin Sheets, 50, pleaded guilty last week to charges of lying to government officials in an effort to cover up his involvement in a …