ORLANDO, Fla. -- Officials on Monday continued to investigate the first fatal accident in the 38-year history of Walt Disney World's monorail, a one-time symbol of founder Walt Disney's vision for future transportation.

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

Three 911 calls made just after the incident were released Monday morning.

"We just heard a loud bang and my manager came running in to tell me to call you," a caller told a dispatcher when describing the incident.

"A monorail was waiting to come into the station, I believe, or did not leave the station and the other one cleared the station and it was a head-on collision," another caller told the dispatcher.

A former monorail pilot spoke with Local 6 about the safety measures on the monorail trains.

"Purple would have been doing what he was told to do and he wouldn’t have been going fast," the former monorail pilot said. "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 pilot said the monorail is equipped with a high-tech anti-collision system that is supposed to automatically stop the trains when they get within 500 feet of each other, but it is typically deactivated at the end of the night as the monorails are being put into storage. She said the trains are also equipped with an emergency kill switch that can be pulled at any moment by a pilot or manager.

"Monorail Central is the one, basically, the main person who should have been hitting it (the kill switch) if these two drivers did not see what was coming, because you're supposed to be standing right there within a foot of that kill switch button, basically," the former pilot said.

The operator of the other monorail was not injured, although he was emotionally shaken and transported to a nearby hospital. At least five 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.

"To see the accident, to see the scene of what had happened and the fact that there was a life that was lost, it was very sad. It was very somber," said Bo Jones, deputy chief for Reedy Creek Fire Department.

Video obtained exclusively by Local 6 News shows guests trying to help the driver who was killed in the crash. The video was recorded by a person who was at the scene when the crash occurred.

"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 launched an investigation into the fatal holiday accident, including the cause of the crash.

The Occupational Safety and Health Administration will also conduct an investigation, which could take as long as six months to complete. The federal agency will look into whether any workplace safety rules were broken.

Monorails at the park were seen moving at about 5:35 a.m. Monday for the first time since the deadly incident. It's not known when the trains will be reopened for guests, however.

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."

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 co-worker 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."

Stay with Local 6 News and ClickOrlando.com for more information about the crash.