Where railroad had long history of unilaterally modifying attendance policy, that practice reflected its authority to do so as an implied term of its collective bargaining agreements with employees.The 7th U.S. Circuit Court of Appeals affirmed a decision by Judge Ronald A. Guzman, Northern District of Illinois. Union Pacific employs hundreds of engineers to operate its locomotives on railroads that traverse 23 states. Many of these engineers are members of the Brotherhood of Locomotive Engineers and Trainmen Union. As a …