LYNN – After years of lengthy negotiations between the city and union representatives, the Lynn Custodians Union, AFSME Local 1736, rejected a proposed contract by a nearly two-thirds margin Tuesday, and has indicated it may seek mediation to resolve the issue.After Union President Mark Raftery denied any new developments in contract negotiations in an interview last Monday, the custodians met Tuesday afternoon to vote on a ratified contract agreement that would have put an end to an 18-month contract standoff between the union and the city.Raftery officially filed the results of the vote with Lynn Personnel Director Joseph Driscoll Friday, who confirmed that union members rejected the proposal by a 77-21 count. Driscoll expressed disappointment in the decision, noting that Raftery had indicated prior to the meeting that the deal should go through.”I was shocked to see and hear this because when you shake hands with a union president and look in his eyes while they tell you that they support the contract, you expect that they are speaking for the other union members,” he said. “I think everybody was shocked that it was voted down.”Driscoll could not get into the specifics of the negotiation, and would not say what, if any, role the recent move of the custodians from the School Department to Inspectional Services played in the vote.”I don’t want to talk about specifics because it would violate the collective bargaining agreement,” Driscoll said. “But when that original petition was passed, they had resisted that change from the beginning.”As of Friday afternoon, Mayor Edward J. Clancy Jr. had not seen any official results of the vote in writing, and declined to comment until he could speak with the city’s labor attorney David Grunebaum on Monday.Driscoll said Grunebaum would consult with city officials to determine what the next step in the negotiations would be, and said Raftery had suggested the possibility of mediation before future contract negotiations.Raftery did not answer or return multiple calls seeking comment.Local 1736 will continue to operate under the terms of their current contract, which has been revised at times since it was originally signed in 2006. Terms of that contract were not immediately available.The battle between the custodians and the city will continue next month, when union representatives will appear before a judge on March 20 for a pre-trial hearing in their civil suit against the city.