The Chicago Teachers Union narrowly averted a strike this week, negotiating right up to the deadline late Monday night before announcing a tentative agreement on a contract with Chicago Public Schools.

Like all union contracts, the results appear mixed. The union held the line on a number of issues like preventing the district from ending its contributions to teachers’ pensions. (New hires in the district will not receive the contribution, but will receive a higher salary to make up for it.)

Mayor Rahm Emanuel tried to eliminate the teachers’ “steps and lanes” wage scale — steps for time teaching, lanes for new credentials like masters degrees — but the tentative agreement preserves it. Teachers will be paying more for health care, but not much. The CTU won new language protecting teachers from layoffs and capping class sizes.