Updated 3:38 p.m. ET
(CBS/AP) CHICAGO - The Chicago teachers' strike moved closer to a resolution Friday, with a school board official saying a "framework" was in place for all major issues and the "heavy lifting" had been done.
David Vitale would not say where each side compromised, and he stressed that union delegates still must vote to end the strike. But the 350,000 public school students affected by the work stoppage were told to expect their first day of class next week.
"Parents should prepare their children to return to school Monday," Vitale said.
Robert Bloch, an attorney for the Chicago Teachers Union, said union leaders expected to complete the contract language in time to present a final package to 700 union delegates sometime Sunday.
As the bargaining dragged on, teachers returned to the streets for rallies to press the union's demands, which include a plan for laid-off instructors to get first dibs on job openings and for a teacher-evaluation system that does not rely heavily on student test scores.
On Thursday, contract talks pushed on for more than 15 hours. Vitale said early Friday that the two sides had worked beyond the evaluations issue and had begun crunching numbers on financial matters.
Union President Karen Lewis said negotiators had many "productive" conversations, but she declined to describe the talks in detail.
"It was a long day," Lewis said. "There were some creative ideas passed around, but we still do not have an agreement."
The union scheduled a Friday afternoon meeting of the delegates who would be required to approve any contract settlement with a majority vote.
About 15 minutes after Lewis entered the meeting, delegates could be seen through the windows cheering and applauding, some on them on their feet and pumping their fists in the air.
Journalists were not allowed inside, and there was no way to know what they were applauding.
The strike by more than 25,000 teachers in the nation's third-largest school district has idled many children and teenagers, leaving some unsupervised in gang-dominated neighborhoods. It also has been a potent display of union power at a time when organized labor has lost ground around the nation.
The union is trying to win assurances that laid-off but qualified teachers get dibs on jobs anywhere in the district. But Illinois law gives individual principals in Chicago the right to hire the teachers they want, and Mayor Rahm Emanuel argues it's unfair to hold principals accountable for their schools' performance if they can't pick their own teams.
The district has offered a compromise. If schools close, teachers would have the first right to jobs matching their qualifications at schools that absorb the children from the closed school. The proposal also includes provisions for teachers who aren't hired, including severance.
It wasn't clear if the union had accepted the proposal, but Lewis said it "did not intend to sign an agreement until these matters are addressed."
Readers of the Sun-Times opened the paper Friday to a full-page letter to Emanuel written by the Boston Teachers Union.
In the letter, the union reminded readers that some of the things Chicago teachers are fighting have long been available to Boston teachers, including the right to let teachers with seniority move into jobs in other schools if their schools close down.
Perhaps more significantly, the union took Emanuel to task for the contentiousness of the negotiations, putting the blame on the mayor's shoulders.
"Perhaps you can learn from us -- and begin to treat your own teaching force with the same respect," the union wrote.
Meanwhile, Chicago teachers said they were planning a "Wisconsin-style" rally for Saturday, regardless of whether there is a deal on the contract.
The union has won widespread support from other teachers unions around the country, and a couple of hundred Wisconsin teachers planned to come to Chicago to join the event.
"It's really sort of a spontaneous kind of organizing," said Bob Peterson, president of the Milwaukee Teachers' Education Association, which unsuccessfully sought the recall of Gov. Scott Walker.
The walkout is the first Chicago teachers strike in 25 years. A 1987 walkout lasted 19 days.