Frustrated at the lack of a new contract, the roughly 375 members of the Mansfield Educators Association are working only regular contracted school hours under a work action its members approved recently. About 125 teachers turned out at the School Committee’s meeting Tuesday night, but were not allowed to speak during the time allotted for citizen comments, said Scott Cohen, the union’s president. “Teachers who are residents of Mansfield were shocked and in disbelief,” Cohen said in an interview. “It’s very unsettling for teachers to work without a contract.” The union’s three-year contract ran out at the end of August, and its members feel disrespected that this is the second contract season that has been settled late, he said. “It’s hard to attract talented teachers when you don’t have a contract,” Cohen said. Superintendent Brenda J. Hodges said the two sides have been meeting with a mediator, and she “is very positive we’ll work this out . . . soon.” She said the work action is not “disrupting the education of our students.” Both sides said they were unable to comment on the details of the negotiations.