The Baltimore school district and its teachers union have struck a landmark agreement that would end the longtime practice of linking pay to years of employment and place the city at the forefront of a national reform effort, according to sources familiar with the pact.

The two sides have discussed a pay system that would reward skills and effectiveness and are expected to announce the details of the agreement Wednesday.

Experts in teacher compensation said Baltimore was poised to become one of only a handful of places in the country, including Washington, D.C., New Haven, Conn., and Pittsburgh, that have moved toward paying teachers for performance as a way to improve the quality of education in their schools. The Obama administration has been pressing for such changes.