LAVAL, Quebec — Members of the Teamsters Canada Rail Conference have voted to reauthorize strikes at CPKC and CN, the union announced Saturday. Overall, 89.5% of union members participated in the vote, with 98.6% voting to reauthorize the strike, the union said. …The union previously authorized strikes at both railroads on May 1, but those authorizations are only good for 60 days, and the potential May 22 strikes have been placed on hold while the Canada Industrial Relations Board rules on a government request to determine if any shipments must continue in the event of a work stoppage. That ruling is still pending. “CN and CPKC are trying to force changes to our collective agreements that would move the clock back on working conditions and rail safety,” TCRC President Paul Boucher said. …The railroads have rejected the unions’ claim that their offers jeopardize safety, saying their latest offers “fully comply with new regulatory requirements for rest.”