An Orange Line train was taken out of service in Chinatown Friday after a passenger allegedly licked the train, the MBTA said.

A passenger told an MBTA employee about the incident around 11 a.m., said Joe Pesaturo, an MBTA spokesman.

The southbound train was taken out of service at the Tufts Medical Center station “out of an abundance of caution,” Pesaturo said in an e-mail.