Close to 600 teachers in Colorado Springs School District 11 held a 1 day strike Wednesday at several locations around the city. The teachers and their union are upset after the D-11 school board let a master agreement between the two sides expire this spring. The district board replaced the agreement with a handbook, that the teachers say falls short of insuring good working conditions for teachers, which also affects students. Board members say they promised the instructors their pay would get better and their working conditions would also improve.