Rick Schwartz, president of the Nashville Zoo, said visitors complained to officials that the 24-year-old train driver appeared to be intoxicated Thursday afternoon and the worker admitted to drinking during her lunch break, WSMV-TV, Nashville, reported Friday.
Schwartz said the driver of the train, which runs on a circular concrete path, was fired.
Customers told officials they had seen Schwartz drop some tokens and fall down while trying to pick them up. She had completed two circuits on the train since her lunch break, officials said.
"We were notified at our Guest Services and went and relieved her," Schwartz said.
The driver's name was not released by the zoo.