ORLANDO, Fla. -- A 21-year-old Walt Disney World employee was killed when two monorails carrying several guests collided at Magic Kingdom, emergency officials said.

Austin Wuennenberg, the operator of one of the monorails, was pronounced dead at the scene after the monorails collided at about 2 a.m. Sunday near the Ticket and Transportation Center.

Disney said it was the first fatal crash in the monorail's 38-year history in the park.

The operator of the other monorail was not injured. Eight other people were evaluated after the crash, but no other injuries were reported.

According to witnesses, a monorail was returning from Epcot when it slammed into the rear of the other train.

"We heard a loud explosion, and you could hear things falling to the floor. We ran to see what it was, and we saw the monorails collided," a witness said.

Video obtained exclusively by WKMG-TV shows guests trying to help the driver who was killed in the crash.

"Is there somebody in here?" a person asked. "Can you hear us? Hey, can you hear me? Can you hear me?"

The monorail, which shuttles thousands of visitors around the sprawling resort each day, was shut down, and the Orange County Sheriff's Office has begun an investigation into the fatal holiday accident, including what caused the crash.

Wuennenberg was a computer science major at Stetson University and was set to graduate in 2010. Wuennenberg, who graduated from Celebration High School in 2006, served as a teacher's aide from August 2007 to May 2008, according to his Facebook page.

Wuennenberg listed his position as "Monorail Pilot," a role he had held since October. He described his job as "running the highway in the sky!" The Facebook page also stated that Wuennenberg worked at Disney in "Sunset Attractions" from June 2006 to September 2008. His interests included video games, computers, programming and comedy.

Wuennenberg's family issued a statement Sunday night.

"Austin Wuennenberg was a senior at Stetson University, studying computer science. He always enjoyed his work at Disney, and especially enjoyed his work as a monorail pilot. He has many great friends whom he has positively influenced; everyone will truly miss this dynamic young man. Austin's family would like to thank friends and well-wishers for their kind thoughts and prayers. We appreciate sensitivity and respect from the media during this difficult time."

A former monorail pilot told WKMG that all Disney monorails are equipped with a sophisticated "anti-collision" system that automatically stops the trains if they get too close to each other. The former pilot said the system must be shut off when the monorails are put into storage for the night.

"In order for that train, the blue train, to get close to that red train, you've got to override the safety system, basically," the former monorail operator said.

Ethan Meus, who was visiting the theme park from Dubuque, Iowa, said he and his family took the monorail to dinner at a resort hotel Saturday night. Meus, 17, watched the Magic Kingdom fireworks from the monorail on the way back to his hotel and didn't notice any problems with the train, he said.

"It's pretty shocking to hear that a driver was killed in that accident," Meus said.

The family was planning to take the train again Sunday to visit Disney's Epcot Center, but now planned to take a bus, Meus added.

"You would think it would be so safe," said 20-year-old Lauren Shoebottom, who was visiting the park from London. "You don't expect it on holiday, do you?"

Walt Disney World Vice President of Public Affairs Mike Griffin issued a statement offering condolences to the employee's family.

"Today, we mourn the loss of a fellow cast member. Our hearts go out to the family and fellow cast members who lost a coworker and a friend. Safety of our guests and cast members is our top priority. We will work with law enforcement to determine what happened," Griffin said in the statement.

Griffin would not comment on the circumstances surrounding the crash.

"They are extremely rare," Griffin said of accidents at the park. "The safety of our guests and cast are a top priority above all else."