(CNN) -- Two monorail trains at Walt Disney World collided early Sunday, killing a 21-year-old driver.

A 2 a.m. ET monorail crash at Disney World killed one person, a park spokesman said.

A witness said one of the trains rammed into the back of a stationary train about 2 a.m. at the resort's Ticket and Transport Center.

There were eight people on board at the time, the Orange County Sheriff's Office said.

A second employee was taken to a hospital to be checked; the six guests -- members of a single family -- were evaluated by paramedics at the scene and released. Disney World officials said none of the seven was injured.

Authorities identified the driver as Austin Wuennenberg, a senior at Stetson University studying computer science.

"It's a terrible day for us," said Mike Griffin, Disney's vice president for public affairs. "Our hearts go out to Austin and his family."

A statement from Wuennenberg's family said, "He always enjoyed his work at Disney, and especially enoyed his work as a monorail pilot. He has many great friends who he has positively influenced; everyone will truly miss this dynamic young man."

The theme park is working with county authorities and the U.S. Occupational Safety and Health Administration in the investigation.

"The safety of our cast and our guests is legendary and it's our top priority," Griffin said. Disney World calls its employees "cast members."

The monorail was shut after the accident, Griffin said.

Images from the scene showed the front car of a train badly damaged where it hit the other train at a station.

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