About a dozen trains headed toward Vienna on Metro’s Orange line  experienced delays of up to 30 minutes Tuesday evening as a result of a switch problem, a Metro spokesman said.

The problem with the switch at Vienna lasted from about 6:30 p.m. to 7:30 p.m., and it delayed five trains by 25 to 30 minutes, and eight more trains by up to 20 minutes, spokesman Dan Stessel said.

The delays came toward the end of a period of heavy rail usage at the close of the workday. Residual delays continued after the problem was resolved, he said.