Chicago Public School teachers, clinicians, and support staff are voting Friday for top union offices.

The major positions are Chicago Teachers Union president, vice president, recording secretary, and financial secretary. There are about 40 other elected positions available in high schools and elementary schools.

The incumbents, President Karen Lewis and Vice President Jesse Sharkey, are running against Tanya Saunders-Wolffe and Mark Ochoa.

25,000 union members are eligible to cast ballots.

Preliminary results will be available sometime between six and nine o’clock Friday.

Lewis led a strike last fall, the first one in 25 years. It lasted seven school days.

Elections are every three years.